Bluetooth-Electronic product solution company-Electronic and electrical product development-Bluetooth design-S

Bluetooth

07-05

2023

Product Show—AC6936D

While ensuring stable performance, AC693N also has the characteristics of low power consumption. Because it is a highly integrated single-chip solution, the chip package is smaller and the user experience is naturally better. Its working voltage is: AC6933C (2.2V~5.5V), AC6936D (2.2V~4.2V).AC6933C and AC6936D are the same chip source. AC6933C is a specially sealed IC model that focuses on the BLE low-end market. AC69336D is mainly used in the Bluetooth headset market. The advantages are low power consumption and good sound quality. The charging compartment is automatically turned on, and TWS can realize manual switching between master and slave.Product application: TWS earphones, central control earphones, unilateral earphones, wearable devices, BLE/SPP transparent transmission moduleBluetooth version: Bluetooth audio 5.0+BLE5.0;1. Solution advantages of Jerry AC6936DJerry's AC6936D hard-core Bluetooth 5.1 chip supports Bluetooth wireless stereo high-speed transmission of lossless audio. AC6936D has a built-in intelligent lossless noise reduction algorithm, which realizes binaural high-definition calls and seamless master-slave switching.Jerry AC6936D adopts industry-leading chip production technology. The power consumption of Bluetooth ear music playback is only 6mA. Combined with high-quality polymer lithium battery, it can play music for 6-8 hours and stand by for 100 hours. Excellent customer experience.AC6936D realizes intelligent power on and off, automatic connection of headphones out of the warehouse, and automatic shutdown when placed in the charging chamber, making it more intelligent and convenient to use. Support intelligent voice AI, connect to voice assistant, and realize intelligent voice interaction function.2. Features of Jerry AC6936D(1) Master-slave switching, intelligent charging compartment;(2) Ultra-small package, high integration, few peripheral materials;(3) Lossless music, HIFI sound quality, ultra-low power consumption; the reference theoretical power consumption is AC693N (6~8mA), the specific power consumption is related to the functions of the product, and the above power consumption is for reference only.(4) MESH networking, convenient configuration tools;(5) Bilateral call, AI intelligence;(6) Gensor knocking; analog digital silicon mark;(7) Intelligent connection, OTA upgrade, built-in charging management, constant current and constant voltage;AC6936D.pdf
07-01

2023

Product Show—AC6901A

Representative models of Jerry's AC69N series are: AC6901A (LQFP48), AC6905A (SSOP24). Since the launch of the AC690N series in December 2016, the low-end Bluetooth market has been highly recognized. According to statistics, the total shipments in 2017 exceeded 400 million units, and the audio market share exceeded 50%. Support BLE4.2+classic bluetooth dual-mode.Application areas: Bluetooth story machine, pure Bluetooth speaker, card-plug Bluetooth speaker, large speaker with pull rod, car Bluetooth, AI smart speaker, point reading pen (voice emission, serial code, magic sound function).1. Brief introduction of Jerry Bluetooth chip AC6901AAC6901A is a single-chip Bluetooth solution launched by Jerry in December 2016. It is packaged in LQFP48 and supports MP3 and WAV. At the same time, it also supports the decoding of lossless formats FLAC and APE, and 24-bit DAC output. It integrates Bluetooth + plug-in card + radio, and the version of Bluetooth is 2.1+EDR. It can be said that this chip is a powerful chip that is the best choice for developing a plug-in card Bluetooth speaker.Jerry’s AC690N series chips are all in one wafer, but they are packaged in different ways according to different needs, that is to say, the AC6901A (LQFP48) and AC6905A (SSOP24) packaged wafers in the AC690N series are the same, AC6901A The chip can be programmed repeatedly. Its operating voltage range is: 3.3V~5.5V, and the theoretical power consumption is 20~25mA. The specific power consumption is related to the functions of the product. This power consumption value is for reference only.2. Chip features of Jerry Bluetooth AC6901A1. High integration: built-in MCU+2.1EDR+BLE4.2+NFC+FM+FLASH; easy production, easy patch, easy maintenance, easy stocking, easy upgrade;2. Rich decoding formats: support MP3, WAV, WMA, FLAC, APE and other decoding formats;3. The sound quality is low noise and the call effect is good: the signal-to-noise ratio of the DAC reaches more than 90dB;4. Powerful main control functions: 32-bit RISC MCU, the system can run up to 200MHz, flexible Bluetooth background, rich peripheral interfaces, support USB, SDIO, UART, SPI, IIC, PWM, IIS, LCD controller, NFC, RTC, TIMER , MIC, ADC, DAC, AUX, touch buttons, recording, reverberation and other functions; card solutions with display, and up to 32 available GPIOs, which can form many functions. Support remote control function. Support USB device, TF card, FM, AUX, Bluetooth. The buttons support 10 stably, and the previous song and the next song can be expanded at will.5. Support TWS: bilateral call;6. Small package: small package LQFP48, pins out on all sides, the smallest package is QFN32 4*4;AC6901A 芯片规格书.pdf
06-26

2023

NFC Bluetooth Quick Connect

Research on Realizing Bluetooth Fast Connection Using NFC TechnologyIn recent years, as people have put forward higher requirements for the intelligent experience of automobiles, the development of automotive electronics has accelerated, further promoting the application of electronics, communication and other technologies in the automotive field. Bluetooth communication technology has always been the main wireless technology for vehicle communication. The traditional car bluetooth relies on the mobile phone to manually connect with the car bluetooth. The steps are cumbersome, and there are often situations such as being stuck or failing to connect, which greatly reduces the interactive experience. In recent years, Near Field Communication (NFC) technology has been greatly developed and matured. NFC technology is an interconnection technology jointly researched and developed by Philips and Sony for non-contact identification. As a standardized short-distance high-frequency wireless communication technology, the working frequency of NFC technology is l3.56MHz, and the communication distance is 5-10cm.Compared with other radio frequency identification (RFID) technologies, NFC has the characteristics of extremely short reading and writing distances. However, this seemingly disadvantage itself limits the monitoring and attack of potential hackers, and has higher security. If the characteristics of these two communication technologies can be cleverly used, it will bring better user experience and communication security, and improve the competitiveness of automotive electronics in the market. Therefore, applying NFC technology to the field of mobile payment has become a research hotspot.1. NFC technical solution1.1 NFC working modeNFC works in three modes: card emulation mode, reader-writer mode, and peer-to-peer communication mode.(1) Card emulation mode. NFC is equivalent to a non-contact IC card in the card simulation mode. It writes some information into a mobile device with an NFC device. After the information is read by an external device, it returns instructions to guide the next operation. Therefore, the NFC mobile device can be used for activities such as mobile payment without changing existing devices.(2) Reader mode. NFC is equivalent to a tag that can be read and written in the reader-writer mode, such as electronic posters, scenic spot maps, etc., and the advertising data and map data are written into the NFC tag, and the handheld NFC mobile device can read it to obtain the required information. Information.(3) Point-to-point mode. In point-to-point mode, NFC can realize data transmission and communication between two mobile devices with NFC. For example, two devices exchange business cards or help the connection between two Bluetooth devices, by exchanging the data necessary for Bluetooth connection, to avoid the tedious operation process of Bluetooth connection.1.2 NFC communication mode(1) Active communication mode. In the active communication mode of NFC, the initiator and receiver alternately generate radio frequency fields. The initiator communicates at a preset transmission speed, and the receiver also needs to respond with load modulation data at the same transmission speed.(2) Passive communication mode. In NFC passive communication mode, the sender generates a radio frequency field. This radio frequency field excites the receiver device. At this point, the sender starts communicating at the agreed speed, and the receiver responds with load-modulated data at the same speed.1.3 NFC architectureNFC technology is based on non-contact technology and is compatible with non-contact Ic card standard (ISO 14443 protocol) wireless communication technology. This technology has become a formal international standard, the ISO 18092 standard (NFC IP-1). The architecture of NFC technology includes the physical layer, data exchange layer, and application layer from bottom to top. The lowest physical layer standards include ISO 14443, ISO 18092, and ISO 15693, as shown in Figure 1. The data exchange layer mainly includes protocol standards for NFC devices to exchange data in three modes.2. Android-based NFC terminalDue to the expansion of the demand for NFC in the field of electronic consumption, the voice of combining NFC technology with mobile phones has gradually increased. This combination not only enables the application of smart phones in the field of electronic consumption, but also will invisibly increase the importance of such smart devices in life. Smart mobile devices with NFC can replace credit cards and electronic smart cards when applied to contactless payment. In addition, the smart mobile device can also be used in real life such as identification, social networking, and bus cards. The NFC terminal is basically similar to the ordinary Android device terminal, but the NFC module is added to realize its functions. System hardware block diagram shown in Figure 2. The NFC module has a communication interface and a control interface. It communicates with the baseband chip through the UART, and realizes the start-up control of the NFC module through the GPIO of the baseband chip. The NFC chip is connected to the SIM card of the mobile phone through the SWP interface, and the SIM card of the mobile phone is used as a security guarantee for the NFC module, storing user information in the SIM card, and the NFC module can read the information through the SWP interface.The baseband chip is the basic module of a standard mobile phone, which can send, receive and process data communication, and provides interfaces with memory modules, power modules, SD cards, WiFi modules, Bluetooth modules, NFC modules, SIM cards, etc. The NFC module mainly includes a power module, a radio frequency module, and a baseband processor module. The power supply module supplies power to the NFC module and controls the power supply; the radio frequency module modulates the baseband information and transmits it, and receives the radio frequency information returned by demodulation; the baseband processor module is responsible for encoding the information and decoding the received data information.2.1NFC module is connected with the baseband chipThe baseband chip realizes complete control of the NFC module, and the UART communication only needs to pass through two transmission lines to complete the sending and receiving of data. Since the UART interface design method is more flexible and convenient, the transmission rate can also be defined by software. Therefore, using the UART interface to connect the NFC module to the baseband chip facilitates the control of the NFC module by the baseband chip without hindering other functions of the mobile phone.2.2 NFC module is connected with SIM cardAs an important security module, the SIM card is connected to the NFC module through the SWP interface, and the NFC reads the pre-stored security information in the SIM card through the SWP interface. Connect with the NFC controller through the C pin (ie swp) on the SIM card to realize full-duplex communication. The RST, CLK, and I/O of the SIM card are directly connected to the baseband chip, and the SWP is connected to the NFC module.3. Combination of NFC and Bluetooth technologyBased on NFC and Bluetooth technology, the main function of vehicle-mounted applications is to use the characteristics of safety, convenience and speed of NFC short-distance communication to replace complex operations such as searching for devices and pairing in the process of Bluetooth transmission and connection. On the basis of NFC, the encryption mechanism that comes with the Bluetooth specification is not used. Before transmitting data, the sender device first sends the Bluetooth MAC address to the receiver device through NFC touch to avoid the generation of a PIN code; After pairing, send data to the other party using Bluetooth non-secure mode.3.1 NFC and Bluetooth hardware connectionThe Bluetooth terminal can quickly pair and connect through NFC, mainly based on the simple security pairing protocol (bluetooth secure simple pairing, SSP) proposed by the NFC alliance. Since the SSP protocol enables out-of-frequency pairing, the NFC link can complete information exchange and participate in the process of out-of-frequency pairing. Therefore, the pairing of the Bluetooth terminal no longer requires cumbersome search connections and PIN code authentication.Due to the establishment of the Bluetooth Advanced Audio Broadcasting Protocol (A2DP) in the current Android 4.0 version, it is more convenient to use NFC to accelerate the Bluetooth pairing process. The pairing process includes the following two steps: first, read the NFC data exchange format (NFC data exchange format, NDEF) record from the external memory, and then perform connection pairing between two Bluetooth terminals.3.2 Fast connection based on NFC car BluetoothThe advantages and disadvantages of NFC technology and Bluetooth technology complement each other, which can accelerate the connection speed of Bluetooth in the car. The simple secure pairing (securesimpleprotocol, ssP) protocol in the Bluetooth technology used by the connection terminal is an NFC-based Bluetooth connection protocol recommended by the SIG and the NFC Forum in 2011. When the SSP protocol uses out-of-frequency pairing, the NFC link can participate in out-of-frequency pairing and complete information exchange. Therefore, the pairing of the Bluetooth terminal does not need to search for connection and PIN code authentication, which can greatly shorten the connection time. It mainly includes the following steps.(1) The Bluetooth OOB data packet specified in the SSP protocol is generated by the processing chip. The data packet contains 2 bytes of OOB data length, 6 bytes of Bluetooth device address and OOB operation data. Among them, the OOB operation data includes the Bluetooth module name, HASHC code, R code, UUID (the globally unique identity code of each service and its attributes in Bluetooth, and the UUID of the Bluetooth connection process service is used here) and the device level code.(2) After the data is generated, the processor packages the OOB data packet into a complete NDEF record according to the NFC data exchange format (NDEF), and sends it by the NFC module of the handheld terminal A.(3) After the transmission is completed, the handheld terminal A controls the listen function of the Bluetooth Socket to enter the listening waiting state.(4) The Bluetooth module of the handheld terminal receives the connection request of the vehicle terminal through the accept function, registers the program UUID with the system, and starts the thread for sending data. In order to strengthen system security, the elliptic curve encryption algorithm is added to the connection pairing process. Using this encryption algorithm, the handheld terminal transmits the ECC key to the receiving device through NFC touch before transmitting OOB data. After the vehicle-mounted terminal decrypts correctly according to the received ECC key, it analyzes the OOB information contained in the record of the handheld terminal, and according to the Bluetooth name, address and unique UUID data in the OOB information, through the connect function in the Bluetooth Socket, it sends data to the handheld terminal. Apply for a connection request. The transmitted data can be encrypted with a key, and then the encrypted information is sent to the other party using the Bluetooth non-secure mode. After receiving it, the receiver decrypts and restores the data, thus completing the data transmission between the two devices. This will greatly improve the security of data transmission while increasing the speed of Bluetooth connection.SummarizeThis paper implements the NFC function based on Android, and proposes a solution to apply it to automotive electronics, and compares the connection time-consuming analysis results of its pairing with traditional Bluetooth through testing. Adding the NFC function module to the Android system is an increasingly strong demand for modern intelligent devices. And then apply it to automotive electronics, whether it is a car phone, Bluetooth audio or electronic key, it simplifies people's life, improves safety during driving, and provides users with a good experience.The above is the method of using NFC technology to realize Bluetooth fast connection introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-25

2023

Bluetooth Security Vulnerabilities and Attacks

Analysis of Security Vulnerabilities and Attack Methods of Bluetooth TechnologyIn current network applications, the Internet of Things has ubiquitous requirements for item diversity, low cost, low speed, and short distance. Such requirements are mainly realized through low-speed network protocols such as Bluetooth. Bluetooth is an open standard for short-distance communication, which uses embedded chips to realize wireless connections with a communication distance between 10m and 100m. The design goal of Bluetooth is to enable personal devices produced by various manufacturers to more easily realize low-speed data transmission and cross-operation through this network protocol through a unified short-range wireless connection standard. Bluetooth technology has the characteristics of low cost, low power consumption, small module size, and easy integration, which is very suitable for application in new IoT mobile devices.1. The security system of Bluetooth technology1.1 Four-level security mode(1) Security mode 1: Security mode l does not have any security mechanism, does not initiate a security program, and has no security functions such as verification and encryption. In this mode, the device runs faster and consumes less, but the data is easily attacked during transmission. . Bluetooth V2.0 and earlier versions support this mode.(2) Security mode 2: Security mode 2 is a mandatory eye layer security mode, and the security program can only be initiated when the logical channel of the channel is established. In this mode, security policies such as authentication requirements, authentication requirements, and encryption requirements for data transmission determine whether to generate an instruction to initiate a security program. All current Bluetooth versions support this mode, and its main purpose is to make it compatible with versions before V2.0.(3) Security mode 3: Security mode 3 is a link layer security mechanism. In this mode, the Bluetooth device must initiate a security procedure before the channel physical link is established. This mode supports functions such as authentication and encryption. Only versions above V2.0 support security mode 3, so this mechanism is less compatible and flexible than security mode 2.(4) Security Mode 4: This mode is similar to Security Mode 2. It is a service-level security mechanism. The ECDH algorithm is used in the link key generation link, which is more secure than the previous three modes and the device pairing process is somewhat different. Simplified, man-in-the-middle attacks and passive eavesdropping can be prevented to some extent. When connecting a device, it is the same as security mode 3 to first determine whether to initiate a security program. If necessary, check whether the key is available. If the key is available, use the simple direct pairing method of SSP to connect through the authentication and encryption process.1.2 Key Management(1) Link key: The link key is a 128b random number, which is activated by the pseudo-random number RAND, personal identification code PIN, and device address through the E21 or E22 stream cipher algorithm. The initial key and combined key are generated through the initialization process and are used as temporary link keys to be discarded after the authentication between devices is completed. The master key can be used by devices to broadcast encrypted information in the piconet, and the master key will replace the original link key when sending broadcast information. After the unit key is generated, it will be saved in the Bluetooth device and will be directly applied to the link communication.(2) Encryption key: The authenticated Bluetooth device can use the encryption key to encrypt the transmitted data during communication. The key is generated by the symmetric encryption algorithm E3 algorithm, the word length is 128b, and is generated by the pseudo-random number RAND, the encryption offset COF generated in the authentication process, and the current link key K. Bluetooth adopts the method of group encryption, the encryption key and other parameters (device address of the main device, random number, Bluetooth clock parameters) generate a binary key stream through the E0 algorithm to encrypt and decrypt the transmitted data.1.3 AuthenticationThe purpose of authentication is to authenticate the identity of the device, and at the same time give feedback on whether the parameter transfer is successful. It can be either a one-way process or a mutual authentication, but both need to generate a link key in advance. The device address of the authenticated device, the random number generated by the authenticated main device, and the link key are all involved, thereby generating a response message and an authentication encryption offset value. The former is passed to the main device for verification. If the same Then the authentication is successful. If the authentication fails, a certain length of waiting time is required before authentication can be performed again. The authentication process is shown in Figure 3.2. Known Bluetooth Security Vulnerabilities2.1 Frequency hopping clock: Bluetooth transmission uses adaptive frequency hopping technology as the spread spectrum method, so the running counter in the frequency hopping system contains a 28-bit frequency hopping clock with a frequency of 3.2kHz, so that the control instructions are strictly in accordance with clock synchronization, information sending and receiving timing and Frequency hopping control thus reduces transmission interference and errors. However, attackers often interfere with the work of the frequency hopping command generator and frequency synthesizer by attacking the frequency hopping clock, so that the Bluetooth devices cannot communicate normally, and use the strong wave penetration and propagation width of the electromagnetic pulse to eavesdrop on the communication Parameters related to content and frequency hopping.2.2 PIN code problem: The personal identification number (PIN) in the key control diagram is four digits, which is the only trusted source for generating the encryption key and the link key. When two Bluetooth devices are connected, the user needs to separate them in the device Enter the same PIN code to pair. Due to the short PIN code, the number of keys in the key space of the encryption key and the link key is limited to 10 orders of magnitude, and if the user uses an overly simple PIN code (such as continuous same characters), long-term Bluetooth devices that do not change the PIN code or use a fixed built-in PIN code are more vulnerable to attack. Therefore, in versions after V2.1, the length of the PIN code is increased to 16 bits, which increases the key space and improves the security of the Bluetooth device connection authentication process, and it will not be caused by using too long data. The string brings inconvenience to communication.2.3 Link key spoofing: The link key used in the communication process is based on the fixed unit key in the device, while other information in the encryption process is public, so there are large loopholes. For example, when device A communicates with different devices, it uses its own unit key as the link key. An attacker uses device C that has communicated with A to obtain this unit key, and can forge another link key that has communicated with A. The device address of device B calculates the link key, and pretends to be B to pass A's authentication, and B pretends to be c as well.2.4 Encrypted key stream repetition: The encrypted key stream is generated by the E0 algorithm, and the generation sources include the main device clock, link key, etc. During a particular encrypted connection, only the clock of the master device is changed. If the device continues to be used for more than 23I3 hours, the clock value will start repeating, resulting in a keystream identical to that used in the previous connection. The repetition of the key stream is easy to be exploited by the attacker as a loophole, so as to obtain the initial plaintext of the transmitted content.2.5 Authentication process/Password in simple and secure pairing: In addition to using the personal identification code PIN for pairing, the Bluetooth standard has added a simple and secure pairing SSP (SecureSimplePairing, SSP) method starting from version V2.1. The SSP method is more convenient than the previous PIN code pairing. Unlike PIN code pairing, which requires two paired devices with input modules to enter the pairing password at the same time, SSP only needs two paired devices with output modules to confirm whether it is displayed on the screen. Just the same random number. Establish a Bluetooth physical connection through device search, generate a static SSP password, and establish a connection in four steps of authentication. However, this association model does not provide protection against man-in-the-middle attacks, and static SSP passwords are easily broken by man-in-the-middle attacks.3. Security Threats of Bluetooth TechnologyThe attack threats against Bluetooth can be roughly divided into two types, one is an attack applicable to different wireless networks, and the other is a specific attack against Bluetooth.3.1 Denial of service attack: The principle of denial of service attack (DOS) is to continuously send connection requests to the attacked target in a short period of time, so that the attacked target cannot establish a normal connection with other devices. The Bluetooth logical link control and adaptation protocol stipulates that the higher-level protocol of the Bluetooth device can receive and send 64KB data packets, similar to ping data packets. For this feature, the attacker can send a large number of ping data packets to occupy the Bluetooth interface, so that The bluetooth interface cannot be used normally, and the bluetooth is always in a high-frequency working state, which drains the battery of the device. The flow chart of DoS attack is shown in Figure 4.3.2 Man-in-the-middle attack: The attacker between two devices intercepts the data sent by one party and then forwards it to the other party, so that the content of the communication between the two parties can be obtained without affecting the communication between the two parties. It is a widely used in wireless networks. attack method. The Bluetooth Low Energy technology (BluetoothLowEnergy, BLE) of the Bluetooth 4.0 version has security measures to prevent man-in-the-middle attacks at the beginning of the design, but in the product stage, considering factors such as product power consumption and cost, this aspect has not received enough attention, and it is still easy. being attacked. The most common is to forge BLE communication with a Bluetooth attack device combined with hardware and software to carry out man-in-the-middle attacks. A schematic diagram of a man-in-the-middle attack is shown in Figure 5.3.3 Vulnerability eavesdropping: Bluetooth eavesdropping can be realized by attacking Bluetooth vulnerabilities. The OBEX (ObjectExchange) protocol in Bluetooth, that is, the object exchange protocol, did not mandate the use of authorization in early Bluetooth product specifications, so attackers can take advantage of this vulnerability Link to the attacked mobile phone without being prompted by the attacked mobile phone, obtain permission to add, delete, and modify various multimedia files and SMS call records in the mobile phone, and even make and answer calls through mobile phone commands. The instruction codes with these attack functions are written by hackers as mobile phone software, which can be downloaded on the Internet. Ordinary people usually use a graphical interface to operate, and some counterfeit mobile phones even have this function. After successfully pairing with other mobile phones, they can obtain the operation authority of the other mobile phone. However, with the continuous improvement of Bluetooth technology, attacks against early Bluetooth vulnerabilities are now becoming less and less common.3.4 Replay attack: The principle of replay attack is to monitor or forge the authentication credentials of the communication between the two parties, and then send it back to the attacked party for authentication after processing. There are 79 channels in the Bluetooth transmission process, and the attacker can attack by monitoring the channel, calculating the frequency hopping sequence, and playing back the IZI command of the authorized device. A protocol to prevent replay attacks has been added to the V4.2 standard.3.5 Pairing eavesdropping: The default 4-digit PIN code of Bluetooth V2.0 and earlier versions is easy to be cracked by violence, because the arrangement and combination of low-digit numbers is very limited, and the LE pairing of Bluetooth V4.0 is the same. As long as the attacker listens to enough data frames, he can determine the key through brute force cracking and other methods, simulate the communication party, and achieve the attack purpose.3.6 Location attack: Each Bluetooth device has a unique 6-byte serial number as the device address. Since this serial identification does not change during use, it is easy to leak the location information of the device. The attacker can obtain the geographical location of the attacked device according to the Bluetooth FM connection mechanism and paging mechanism, device identifier and other communication parameters.3.7 Simple pairing mode attack: The SSP secure simple pairing connection method stipulated by Bluetooth V2.0 is not safe, because it uses a static password and cannot prevent man-in-the-middle attacks, and once the attacker obtains the password, it can be used within a period of time Make persistent attacks.SummarizeWith the rapid promotion of Internet of Things technology in manufacturing, agriculture, and household equipment, the application prospects of Bluetooth cannot be underestimated, but it is also facing greater challenges. Therefore, we look forward to further implementing the necessary security strategies in the future design of the Bluetooth standard. At the same time, when using Bluetooth devices for transmission, we should also increase the security awareness of the use of Bluetooth devices and try to use the strongest security mode.The above is the analysis of security vulnerabilities and attack methods of Bluetooth technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-24

2023

Bluetooth protocol stack architecture

1. Bluetooth core protocol architectureThe Bluetooth core protocol includes Baseband Protocol (Baseband), Link Management Protocol (LMP), Link Control Protocol (LCP), Logical Link Control and Adaptation Protocol (L2CAP), Service Discovery Protocol (SDP) and Serial Port Emulation Protocol (RFCOMM ). Among them, the baseband and link controller and the link management protocol belong to the low-level transmission protocol. Their functions focus on the physical realization of voice and data wireless transmission and the connection and networking between Bluetooth devices. These functions are integrated in the Bluetooth hardware module. , application developers for high-level protocols do not need to care about the details of these low-level protocols; Logical Link Control and Adaptation Protocol and Host Control Interface (HCI) belong to high-level transmission protocols, which shield high-level application profiles such as frequency hopping sequences Select and other low-level transmission operations, and provide high-level applications with more beneficial and more effective data packet formats; based on the TS07.10 standard of the European Telecommunications Standards Institute (ETSI), the serial port emulation protocol (RFCOMM) has been formulated; this protocol uses In order to simulate the working environment of the serial port, the traditional application based on the serial port can directly run on the protocol layer without any modification or only a small amount of modification; the Service Discovery Protocol (SDP) is used to realize the mutual query between Bluetooth devices and Ability to access services provided by the other party.2. Bluetooth upper layer application frameworkThe Bluetooth application protocol profile refers to the application software located on the upper layer of the Bluetooth protocol stack and the protocols involved, including the development of Bluetooth applications that drive functions such as voice communication and dial-up Internet access. All kinds of Bluetooth products have developed corresponding application frameworks for them by SIG. The application framework mainly defines some common functions or the protocols used to realize specific Bluetooth products, the interoperability requirements of each Bluetooth protocol, and the realization functions of each function.Bluetooth application frameworks can be divided into five categories:(1) Application framework: The application framework in the general application model is the basis of all other application frameworks. They specify the application frameworks in other application models and are the functional processes commonly used by all other application frameworks, such as device query, connection Establish and discover services, etc.; (2) Bluetooth phone application framework: application framework related to voice applications and phone control; (3) Bluetooth networking application framework: use Bluetooth devices to provide users with the establishment of personal local area networks and wireless access Public switched telephone network; (4) Object exchange application class framework: used to realize interoperability applications of different types of data objects, such as files, electronic business cards, images, etc.; (5) Bluetooth audio and video application framework: based on network applications audio and video transmission, control, and distribution applications.3. Bluetooth networking technologyBluetooth technology is a short-distance wireless communication technology that supports point-to-point or point-to-multipoint data and voice services. The Bluetooth system adopts a flexible networking method without a base station, so that a Bluetooth device can be connected to other multiple Bluetooth devices at the same time, thus forming a Bluetooth piconet (Piconet); a Bluetooth piconet can be just two connected devices (such as As shown in Figure 2.12a), such as a laptop and a mobile phone, or multiple devices connected together (as shown in Figure 2.12b); the Bluetooth piconet adopts a master-slave When the network was first built, one of the Bluetooth devices was defined as the master device, and the rest were slave devices; a master device can communicate with up to seven slave devices at the same time, and the slave devices here are called active slave devices (ActiveSlave); but at the same time There can be multiple dormant (Parked) slave devices belonging to the master device; these dormant slave devices do not perform actual effective data transmission and reception, but still maintain clock synchronization with the master device so that they can quickly join the piconet in the future. Regardless of the state of the device, whether it is a dormant slave device or an active slave device, the master device of the piconet controls the parameters of the channel. In the piconet, the master device communicates with all active slave devices through a certain polling method, and uses methods such as designated time slots to enhance the communication between the master and the slave and the communication between the slave and the slave.Bluetooth Scatternet (Scatternet) is formed by interconnecting multiple piconets. As shown in Figure 2.12c/2.13, a scatternet is a bluetooth network with a larger coverage area than a piconet composed of overlapping piconets. The slave device can join different piconets through the time division multiplexing mechanism, and the master device of one piconet can become the slave device of another piconet. Each piconet has its own frequency hopping sequence, and there is no frequency hopping synchronization between them, which reduces the interference of the same frequency.The above are the details of the Bluetooth protocol stack architecture and networking technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-23

2023

Bluetooth anti-electromagnetic interference performance

Test and Analysis of Anti-electromagnetic Interference Performance of Bluetooth TechnologyThe common frequency band of Bluetooth technology in the world is 2.4GHz. Due to the strong openness of its frequency band range, it is inevitable to be subject to external electromagnetic interference during use, which affects the stability and security of data transmission. It is conducive to the wide application of bluetooth technology. Therefore, it is of great significance to explore the anti-electromagnetic interference performance of bluetooth technology and propose improvement countermeasures.1. Overview of Bluetooth technologyBluetooth is a radio technology suitable for short-range communication between devices, enabling real-time transmission and sharing of data. For example, the application of Bluetooth technology in mobile phones, PDAs, wireless headsets, notebook computers and emerging wearable devices can realize real-time transmission and sharing of information. Through the full use of Bluetooth technology, the speed of data transmission can be effectively improved, the communication process between mobile devices can be simplified, and a good foundation has been laid for the research of wireless communication. Bluetooth adopts distributed network structure and frequency hopping spread spectrum technology, supports point-to-point and point-to-multipoint communication, and its data rate can reach 24Mbit/s. At the same time, Bluetooth technology adopts a time-division duplex transmission scheme, which can fully realize full-duplex transmission, and has higher advantages compared with traditional data transmission methods.1.1 Bluetooth technical characteristicsBluetooth technology is a wireless communication technology integrating low power consumption, short-distance data transmission and openness. It is jointly released by Intel Ericsson, Nokia, Toshiba and International Business Machines Corporation. On the basis of making full use of short-distance and low-cost wireless transmission technology, Bluetooth technology establishes a complete short-range wireless connection station between fixed equipment and wireless communication equipment, which can realize real-time data transmission within a specific range. In fact, Bluetooth technology is to realize the effective control of software by establishing radio and radio air interface, that is to say, Bluetooth technology is an organic combination of computer technology and communication technology. The technical characteristics of Bluetooth mainly include the following points: 1) low power consumption; 2) low cost; 3) short distance; 4) high security: 5) real-time performance; 6) high-speed frequency hopping. Bluetooth technology can link various mobile devices, fixed communication devices, computers and other wearable devices in a network at the lowest cost within a short distance to form a peripheral interface for data transmission.1.2 Main features of Bluetooth technologyFirst, Bluetooth technology uses the open ISM frequency band in the industrial, medical and scientific fields. The working range is 2.4GHz~2.4835GHz. for convenience. Second, Bluetooth technology can realize short-distance data transmission, and its working distance generally does not exceed 10m, and the maximum can be increased to 100m. By expanding the working range of Bluetooth, on the basis of ensuring the data transmission rate, effective immunity to electromagnetic interference can be realized, which has high security. Third, by increasing the application of frequency hopping and spread spectrum technology, Bluetooth technology usually divides 79 frequency points in the 2.4GHz~2.4835GHz frequency band, adopts a fast hopping rate, and the speed of data transmission is significantly improved compared with before. Anti-interference performance is also higher. Fourth, Bluetooth technology adopts time-division multiplexing multiple access technology: the data is packaged into data packets and transmitted in units of time slots. In this way, the problems of "collision" and "hidden terminals" in wireless communication are solved.2. Anti-electromagnetic interference type of Bluetooth technologyThe types of electromagnetic interference in Bluetooth technology mainly include two types: suppressing electromagnetic interference and avoiding electromagnetic interference. Avoiding electromagnetic interference refers to effectively avoiding electromagnetic interference by reducing the transmission signal level between each unit, while suppressing electromagnetic interference requires spread spectrum technology and recoding. For example, when the power is greater than 50dB and the environment is different, in order to ensure the rate of Bluetooth technology up to 24Mb/s, it is difficult to achieve only relying on coding technology, because electromagnetic signals are easier to interfere in a lower power environment, so the power should be selected sent in higher cases. If the time avoidance method is adopted, once strong electromagnetic interference occurs, the data transmission will be interrupted. At the same time, because some wireless communication devices are greatly affected by the bandwidth, between 2.4GHz and 2.4835GHz, the frequency of wireless communication devices With a bandwidth of 80MHZ, it is possible to find a frequency spectrum without electromagnetic interference, and use a filter to filter it to achieve effective suppression of electromagnetic interference. Accordingly, it is considered that the application of the frequency domain interference avoidance method in the Bluetooth technology data transmission process is strengthened, and the security of data transmission is higher.3. Anti-electromagnetic interference performance test and analysis of Bluetooth technologyRealizing short-distance wireless transmission of data is the fundamental goal of Bluetooth technology application. At this stage, Bluetooth technology has been widely used in short-range communication with its advantages of high transmission speed and simplicity and convenience, and has a good application prospect in the field of home and office. But at this stage, the data transmission stability of Bluetooth technology needs to be further improved, and the anti-noise and electromagnetic interference performance needs to be improved. In this study, microwave ovens commonly used in households are selected as the research object, and its working range is 2.4GHZ. The factors affecting the anti-interference performance of Bluetooth communication technology are explored, and the report is as follows.3.1 Bluetooth anti-jamming experimental instruments and equipmentIn this study, the microwave oven is used as the main interference source, and the operating frequency of the microwave oven is 2450MHZ. The stopwatch is used as a time measurement tool, and the size of the transfer file is mainly 100K and 18O0K.3.2 Experimental Principle of Bluetooth Anti-jammingIn this study, two test files with different sizes are selected, namely 1800K and 1OOK. During the experiment, the distance between the Bluetooth transceiver is set as dl, and the distance between the interference source and the Bluetooth transceiver is d2. Research the data transmission rate under the condition of different distances between the interference source and the Bluetooth open system. In the process of testing the influence of interference sources on voice transmission, the voice distortion is mainly tested by the senses.3.3 Bluetooth anti-jamming experimental resultsThrough in-depth analysis of the results of this study, we can see that the design of the Bluetooth communication system is more scientific and reasonable. In the process of transmitting small files, the influence of interference sources on file transmission is almost non-existent. In the process of transmitting large documents, the Bluetooth system only has a slight impact on the transmission speed and time when the distance from the interference source is the closest. Tests of speech transmission under normal conditions under various conditions showed no speech distortion.At the same time, after this test analysis, it can also be known that the interference source selected in this research-the microwave oven has a small transmission power, which is also the main reason why the noise interference has no obvious impact on the transmission time and rate of the Bluetooth system. It proves that the application of the Bluetooth system in the family has high feasibility, and its anti-jamming performance is enough to meet the family's demand for Bluetooth anti-jamming performance. However, in the process of applying the Bluetooth system in the industrial, medical and scientific fields, the transmission power of the interference source is much higher than that of the induction cooker, which poses a huge challenge to the anti-interference ability of the Bluetooth system. Therefore, in order to achieve high-quality communication, it is necessary to further improve the anti-electromagnetic interference performance of the Bluetooth system.4. Effective countermeasures to improve the anti-electromagnetic interference performance of Bluetooth technology4.1 Analysis of the interference problem in the Bluetooth working frequency bandThe electromagnetic interference problem of the Bluetooth system operating in the 2.4GHZT frequency band mainly has the following two points: First, it comes from the electromagnetic interference inside the Bluetooth system. In the process of designing the internal circuit and interface of Bluetooth, if there is an unreasonable design phenomenon, it will cause the high-frequency electromagnetic radiation inside the Bluetooth system to radiate outwards, which will reduce the stability of the internal circuit of the Bluetooth system and is not conducive to improving the transmission of the Bluetooth system. speed. Second, electromagnetic interference from existing services. At this stage, although the communication between high-frequency Bluetooth devices generally relies on frequency hopping and direct sequence spread spectrum, and its transmission power is also within the range allowed by the country, it is affected by the antenna form, system structure and gain index of the Bluetooth system. Modulation schemes, frequencies, and guard bands of communication equipment all have significant differences. In addition, the 2.4GI-IZ frequency band has strong openness, and the use of the frequency band is more complicated, which increases the source of electromagnetic interference.4.2 Bluetooth anti-jamming solutionFirst, for the internal interference of the Bluetooth system, designers should pay attention to improving the rationality of the circuit design of the Bluetooth system in the process of improving the Bluetooth system, so as to minimize the electromagnetic interference. Second, in view of the electromagnetic interference from the existing business, the designers need to focus on the research on the electromagnetic interference between the unified frequency Bluetooth system on the basis of arranging the radio frequency command for the wireless business, and rely on the frequency hopping technology to realize the anti-electromagnetic interference effective resistance. For example, a designer has strengthened the application of adaptive frequency hopping technology in the Bluetooth system in response to the problem of electromagnetic interference, enabling the Bluetooth system to automatically adjust its own frequency range in different situations to achieve effective avoidance of current electromagnetic interference , improve the pertinence of frequency hopping, and achieve effective resistance to electromagnetic interference. Through the application of adaptive frequency hopping technology, the environmental applicability of the Bluetooth system can be fully improved, and on the basis of ensuring data transmission time and rate, it can effectively resist electromagnetic interference and has high application value. In summary, through the test and analysis of the anti-electromagnetic interference performance of Bluetooth technology, it is found that the transmission power of the interference source, the internal interference of the Bluetooth system, and the existing services will have a certain impact on the anti-interference ability of the Bluetooth system.SummarizeThrough research, it is found that the transmission power of the interference source is an important factor affecting the transmission speed of Bluetooth technology. Therefore, in order to fully improve the anti-interference performance of Bluetooth technology, the internal and external circuit design of the Bluetooth system should be continuously improved, the application of adaptive frequency hopping technology should be increased, and the anti-electromagnetic interference ability of the Bluetooth system should be comprehensively improved.The above are the details of the test and analysis of Bluetooth anti-electromagnetic interference performance introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-22

2023

The principle of car bluetooth technology

The principle of bluetooth technology and its application in the field of automobileBluetooth is a wireless communication technology that supports short-distance communication of devices (usually within 10 meters). Data communication between many devices such as peripherals. Bluetooth can effectively simplify the communication between mobile communication terminal equipment and between equipment and the Internet, so that data transmission becomes more rapid and efficient.With the development of science and technology, Bluetooth technology is playing an increasingly important role. Bluetooth technology is closely related to people's lives, and people's demand and dependence on Bluetooth are increasing day by day. This paper analyzes the principle of bluetooth technology, and discusses the application of bluetooth technology in the field of automobiles.1.The principle of Bluetooth technology1.1 Bluetooth protocol stackFigure 1 shows a schematic diagram of the bluetooth protocol stack architecture. The goal of the Bluetooth protocol is to allow applications that follow the specification to interoperate. To achieve interoperability, applications on communicating devices must run on the same protocol stack. So far, the Bluetooth protocol has 1.0, 1.1, 1.2, 2.0, 2.1, 3.1, 4.0, 4.1 and other versions. With the evolution of the protocol and the development of technology, the data rate is gradually increased. The 1.0 version of Bluetooth is the basic bit rate (BR, Basic Rate), the maximum physical layer data rate is 1Mbps; the 2.0 version is the enhanced bit rate (EDR, Enhanced Data Rate), and its physical layer data transmission rate is increased to 2Mbps or 3Mbps; the 3.0 version The introduction of alternative radio frequency technology (AMP, Alternative MAC PHY), using IEEE 802.11 to achieve a physical layer data rate up to several 100Mbps. Version 4.0 introduced Bluetooth Low Energy (BLE, Bluetooth LowEnergy). From the perspective of protocol support, Bluetooth devices can be basically divided into three categories: classic devices, dual-mode devices (supporting both classic Bluetooth and BLE), and single-mode devices (only supporting BLE). Single-mode devices are called Bluetooth Smart, and dual-mode devices are called Bluetooth SmartReady. It should be noted that single-mode devices can only communicate with dual-mode devices, not classic Bluetooth.Figure 1 Schematic diagram of the bluetooth protocol stack architecture(1) The radio frequency (RF, Radio Frequency) layer defines the frequency band and channel arrangement, the requirements that transmitters and receivers working in this frequency band should meet, etc., and realizes the filtering and transmission of data streams.The baseband (BB, Baseband) layer protocol provides two physical links: a connection-oriented synchronous mode (SCO, Sychronous Connection-Oriented) and a connectionless asynchronous mode (ACL, Asychronous Connection-Less).Link Management Protocol (LMP, Link Manager Protocol) is responsible for link establishment, control and link security. LMP performs identity authentication and encryption through connection initiation, exchange, and verification, and determines the size of baseband data packets through negotiation; LMP controls the energy-saving mode and work cycle of wireless devices.The host control interface (HCI, Host Controller Interface) is the interface between the underlying hardware and the upper layer protocol, providing instructions for accessing hardware functions such as baseband, link controller, link manager, and status registers.(2) Logical Link Control and Adaptation Protocol (L2CAP, LogicalLink Control and Adaptation Protocol) belongs to the data link layer. L2CAP provides connection-oriented and connectionless data services for upper-layer protocols. Segmentation and reorganization and delivery of quality of service. L2CAP allows high-level protocols to send and receive data packets in 64K bytes, and L2CAP only supports ACL. The priority of sending LMP messages is higher than that of user information, so the messages sent by LMP will not be delayed due to L2CAP communication. LMP is mainly used to control data transmission, while L2CAP provides packet transmission and control to the upper layer.(3) The Bluetooth Telephone Control Protocol (TCS-BIN) defines call control signaling for establishing voice and data calls between Bluetooth devices, and handles the mobility management process of TCS devices. AT-commands defines a set of commands for controlling mobile phones and modems in multi-user mode.(4) AVCTP (Audio/Video Control Transport Protocol) describes the exchange message transmission mechanism of A/V equipment. AVDTP (Audio/Video Distribution Transport Protocol) defines the negotiation, establishment and transmission mechanism of A/V streams.(5) Service Discovery Protocol (SDP, Service Discovery Protocol) is a protocol based on the client/server structure, and the client application discovers the existing server and its attributes through SDP. SDP only provides mechanisms for discovering services, but not methods for consuming those services. Almost all Bluetooth devices support the SDP protocol, except for the Bluetooth devices that only do Client.(6) Cable emulation protocol The RFCOMM protocol is a serial port emulation protocol based on the technical standard (ETSI) 07.10 of the European Telecommunications Standards Institute. The RFCOMM protocol provides emulation of the RS-232 serial port on L2CAP.(7) Attribute protocol (ATT, Attribute protocol) was introduced for BLE in version 4.0, which allows devices to show device capabilities to other devices in the form of "attributes".(8) Bluetooth Network Encapsulation Protocol (BNEP, Bluetooth Network Encapsulation Protocol) directly bears IPv4/IPv6 through L2CAP.(9) OBEX defines data objects and communication protocols for exchanging these objects, and OBEX is also used for IrDA simulation. In Bluetooth protocol version 1.0, OBEX is carried by RECOMM, while in BR/EDR, OBEX is based on TCP/IP carried by BNEP.1.2 Bluetooth application scenarios and profilesAs shown in Figure 1, according to the purpose of the protocol and its association with the Bluetooth Special Interest Group (SIG), Bluetooth protocols can be classified into the following categories:(1) Bluetooth Core Protocols (Bluetooth Core Protocols), including RF, BB, LMP, L2CAP, SDP, and AUDIO; (2) Adaptation protocols, including RFCOMM, ATT, and BNEP; (3) Telephony Control Protocols , including TCS Binary and AT-commands; (4) A/V control protocols, including AVCTP and AVDTP; (5) Reference protocols (Adopted Protocols), including PPP, UDP/TCP/IP, OBEX, WAP/WAE, vCard/ vCal and IrDA. For specific Bluetooth application scenarios (Bluetooth Usage Models), in order to maintain compatibility and interoperability between Bluetooth devices more easily, the Bluetooth specification introduces Profile.Profile defines the protocol covered by an application scenario and the features necessary to support Bluetooth device communication. The most basic profiles are general access applications (GAP, Generic Access Profile) and general attribute applications (GATT, Generic Attribute Profile). GAP carries traditional BR /EDR, while GATT carries BLE. Figure 2 illustrates the hierarchical relationship between the Bluetooth protocol and Profile.Figure 2 Bluetooth Profile and protocol hierarchy relationshipIn addition to GAP, commonly used profiles include SDAP (Service Discovery Application Profile), SPP (Serial Port Profile), and GOEP (Generic Object Exchange Profile). The Profile list adopted by the Bluetooth SIG can be found on the Bluetooth development portal (http://developer.bluetooth.org). The Hands-Free Application Protocol Framework HFP mentioned below is one of them.1.3 Typical Bluetooth system frameworkA typical Bluetooth system includes a wireless unit, link controller, link management and interface, software protocol, and host terminal.As shown in Figure 3, the host terminal is responsible for functional modules and Bluetooth communication control, and other modules implement Bluetooth communication.In practical applications, the chip basic circuit set that integrates several Bluetooth functions is usually called a Bluetooth module, and subsequent development is carried out on the basis of the Bluetooth module, which greatly simplifies the development of Bluetooth applications.The world's major chip manufacturers are actively investing in the research and development and testing of Bluetooth modules, and have launched Bluetooth modules covering different protocol stack levels. For example, CSR in the UK owns or once owned three kinds of Bluetooth modules, HCI ROM, HCI RFCOMM ROM and Full embedded solution.(1) HCI ROM only covers the protocol layer below HCI. The hardware HCI interface usually uses UART/USB/SDIO, while the L2CAP protocol layer in Figure 1 needs software implementation and runs on an external processor.(2) The difference between HCI RFCOMM ROM and HCI ROM is that it integrates RFCOMM and L2CAP into the chip, which can reduce the code amount of the host processor, but the data throughput rate will be affected.(3) Full embedded solution covers all protocol layers of Bluetooth, and the most popular one is this Bluetooth module.2.The application of Bluetooth technology in the automotive fieldWith the maturity and development of bluetooth technology, bluetooth technology has been used more and more widely, and the automotive field is one of the most active fields. According to the statistics of ABI Research, it is estimated that by 2017, there will be 60 million cars equipped with Bluetooth technology. Compared with 2013, the market growth rate has increased by 47%.2.1 Car hands-free systemCar hands-free system is a typical application of Bluetooth technology in the automotive field. The system uses the mobile phone as the gateway, and the mobile phone supporting the Bluetooth function can be placed anywhere within 10 meters of the vehicle-mounted hands-free system. call.The Hand Free Profile (HFP) specifies the minimum set of functions required for a mobile phone to interact with a hands-free device (vehicle or headset) via Bluetooth. The protocol stack of the Hand Free Profile is shown in Figure 4. HFP defines two roles: voice gateway (AG, AudioGateway) and hands-free unit (HF, Hand-free). Among them, the voice gateway provides audio input and output and its control, and the typical voice gateway is a Bluetooth mobile phone; the hands-free unit provides remote control function, and can use the vehicle-mounted hands-free equipment.2.2 Vehicle detection system based on Bluetooth OBDThe on-board diagnostic system (OBD, On-Board Diagnostics) can monitor the working conditions of the engine electronic control system and other functional modules of the vehicle in real time during the running of the vehicle. Stored on memory within the system as diagnostic trouble codes. With the improvement of various sensors and electronization of vehicles, OBD has added various monitoring functions.As the communication interface of the on-board monitoring system, the OBD interface can provide data such as fuel consumption records, battery voltage, air-fuel ratio, throttle opening, and the number of knocks, in addition to reading fault codes for vehicle repair. The data can be read out through a dedicated data cable and then displayed on the matching display screen. The more convenient way is to add a Bluetooth OBD interface adapter and a smart phone software. At present, many kinds of Bluetooth OBD modules are launched on the market, and the data read by the OBD interface are transmitted to the smart phone through Bluetooth, and then presented to the user through the software of the mobile phone.2.3 Bluetooth Rearview MirrorBluetooth rearview mirror is to add Bluetooth technology to the rearview mirror of the car, so that the rearview mirror can increase the hands-free call function. quality.SummarizeIn addition to the automotive field, the typical application fields of Bluetooth technology include wireless office, information appliances, medical equipment, school education and factory automatic control. It can be predicted that with the advancement of technology and the reduction of production costs, the application field of Bluetooth technology will expand, which will further change people's life and work methods, and significantly improve the quality of life and work.The above is the principle of Bluetooth technology and its application in the automotive field introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad, including MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, and wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-17

2023

AK1052C Bluetooth BLE dual-mode audio module

AK1052C_BT_Module is a high-performance Bluetooth BLE dual-mode audio module for wireless stereo Bluetooth card speakers. This module realizes the core functions of Bluetooth speaker products, including Bluetooth communication, audio codec, system control, card playback, U disk playback, and support for infrared remote control. Because it supports the BLE data transparent transmission protocol, it can communicate with the IOS system for Bluetooth data. Therefore, this module can be used as a Bluetooth point reader, a Bluetooth handwriting point reader, and other products that require data interaction control with the mobile APP. The normal communication distance of Bluetooth is 10M, and the maximum communication distance is 20M.AK1052C_BT_Module integrates main control chip AK1052C, bluetooth chip RTL8761AT, 2MB SPI flash and crystal oscillator etc. Reserve the Bluetooth antenna interface and provide rich peripheral interfaces, including USD2.0, SD/TF card interface, stereo audio output interface, microphone interface, line-in interface, AIN analog key interface, GPIO interface.External SPI FLASH, the capacity can be selected from 16M~128MClass 2 power levelComply with Bluetooth V4.0 specification and Bluetooth V2.1+EDR specificationSupport A2DP, AVRCP, HFP, SPP, ATT protocolsBluetooth communication distance: there is no obstacle in the line of sight, the normal communication distance is 10m, and the maximum communication distance is 20mProvide AIN button interfaceProvide LED status indicator control interfaceProvide Line-in audio input interfaceProvide stereo audio output interfaceBuilt-in lithium battery charging circuitWorking voltage range: 3.4V~4.2V, support lithium battery and USB power supplyModule size: 27.5mm*21.0mmThe standard configuration is 2MB SPI Flash, which can be flexibly configured according to user needsReserved TWI interfaceProvide IRDA infrared remote control interfaceProvide SD/TF card interface for connecting SD/TF memory card, maximum support 32GBProvide USB Host interface for connecting U disk, maximum support 64GB U diskProvide USB Slave interface for program burning and USB sound card functionBuilt-in audio decoder, supports audio decoding in AMR, APE, FLAC, MP3, OGG, WAV, WMA formatsSupport Bluetooth stereo playback, compatible with various handheld Bluetooth devices such as mobile phones and tabletsSupport Line-in audio playbackSupport infrared remote control functionProvide Ankai standard mobile APPS client (Android, iOS) and source code.The client can realize the following functions (mobile phone music playback, remote TF card music playback, remote U disk music playback, Bluetooth speaker power display, Bluetooth speaker volume control, EQ sound effect settings, support pop, rock, classical, soft, vocal and Customization, etc., system information display (device name., software version, product serial number, etc.)Built-in lithium battery charging circuit, support lithium battery charging
07-17

2023

AK1055C Bluetooth single-mode audio/dual-mode audio module

Single mode audio:AK1055C V2.1 Bluetooth single-mode audio module is a single-mode audio module specially launched for Bluetooth speakers. The core board of the product development module uses AK1055C as the main control chip, which is matched with the Bluetooth radio frequency chip RDA5876. Realize the core functions of Bluetooth speaker products, including Bluetooth stereo playback, Bluetooth calls, line in playback, voice prompt status switching, etc. The normal communication distance of Bluetooth is 10 meters, and the maximum communication distance is 20 meters.Built-in a 16M SPI FLASHClass 2 power levelComply with V2.1＋EDR Bluetooth specificationSupport A2DP, AVRCP, HFP protocolsBluetooth communication distance: there is no obstacle in the line of sight, the normal communication distance is 10m, and the maximum communication distance is 20mProvide AIN button interfaceProvide LED status indicator control interfaceSupport 16-bit ADC dual-channel Mic/Line-in input2-way 22-bit DAC output high-quality audio outputWorking voltage range: 3.4V~4.2V, support lithium battery and USB power supplyBluetooth stereo playbackLINE_IN playcharging functionDual Mode Audio:AK1055C_BT_Module is a high-performance Bluetooth BLE dual-mode audio module for wireless stereo Bluetooth speakers. This module implements the core functions of Bluetooth speaker products, including Bluetooth communication, audio codec and system control. Because it supports the BLE data transparent transmission protocol, it can communicate with the IOS system for Bluetooth data. Therefore, this module can be used as a Bluetooth point reading pen, a Bluetooth handwriting point reading pen and other products that require data interaction control with the mobile phone APP. The normal communication distance of Bluetooth is 10M, and the maximum communication distance is 20M.AK1055C_BT_Module integrates the main control chip AN1055C, Bluetooth chip RTL8761AT and crystal oscillator, etc., and provides a wealth of peripheral interfaces, including USB2.0 interface, headphone interface, microphone interface, AIN analog key interface, GPIO interface.Built-in a 16M SPI FLASHClass 2 power levelComply with Bluetooth V4.0 specification and Bluetooth V2.1＋EDR specificationSupport A2DP, AVRCP, HFP, SPP, ATT protocolsBluetooth communication distance: there is no obstacle in the line of sight, the normal communication distance is 10m, and the maximum communication distance is 20mProvide AIN button interfaceProvide LED status indicator control interfaceSupport MIC and Line-in audio input interface2-way 22-bit audio DAC2-way 16-bit audio ADCBuilt-in lithium battery charging circuitWorking voltage range: 3.4~4.2V, support lithium battery and USB power supplyModule size: 17.5mm*25.0mmSupport Bluetooth stereo playback, support EQ sound effectSupport Line-in audio playbackSupport Bluetooth background connection, can perform speed dial and call answering operationsSupport personalized voice prompts, such as caller ID, Bluetooth connection prompts, function mode promptsProvide Ankai standard mobile APPS client (Android, iOS) and source code. The client can realize the following functions (mobile phone music playback, bluetooth speaker power display, bluetooth speaker volume control, EQ sound effect setting, support pop, rock, classical, soft, human voice and custom, etc., system information display (such as device name, software version, product serial number, etc.).Support lithium battery power supply and support charging function.
07-12

2023

Bluetooth CNC DC Voltage Source

Design of Bluetooth NC DC Voltage Source with Chinese Voice Prompt FunctionWith the rapid development of science and technology, and people's demand for low power consumption and high efficiency of electrical appliances, DC voltage sources are developing towards higher flexibility and intelligence. However, the current numerically controlled DC voltage source has problems such as low adjustment accuracy, inconvenient observation of the output voltage value, and insufficient output voltage accuracy. Therefore, this paper designs a digitally controlled DC voltage source with the STC12C5A60S2 microcontroller as the core. The power supply can realize the following functions: the output voltage is adjustable from 0 to 10V, the step is 0.1V, the output current is 500mA, the output voltage value can be remotely adjusted through the Bluetooth device, and there will be a Chinese voice prompt every time the output voltage value changes.1. The overall design of Bluetooth CNC DC voltage sourceThe design block diagram of this design is shown in Figure 1. The voltage source uses 12C5A60S2 single-chip microcomputer as the control chip, and the output 8-digit digital value is converted into an analog voltage value through the D/A module, and then amplified by the amplifier module. Then the current is amplified by the output drive module to increase the load capacity and then output. The output voltage value is displayed through seven-segment digital tubes. The output voltage can be adjusted by changing the output value of the single chip microcomputer. After the output voltage is sampled, it is input to the built-in A/D module of the microcontroller for sampling feedback, so as to realize closed-loop adjustment of the output voltage and ensure the accuracy of the output voltage. The power supply has also added the HC⁃05 Bluetooth module, the user can adjust the voltage value of the power supply or query the current output voltage value with the APP on the mobile phone through the Bluetooth protocol. By adding the SYN6288 voice module, the function of Chinese voice prompt is also realized.2. Bluetooth CNC DC voltage source hardware circuit designThe circuit design of each module is described below.2.1D/A module and amplifier moduleThe D/A module is composed of DAC0832 chip and LM358 operational amplifier module. The DAC0832 chip is an 8-digit/analog conversion chip. The conversion result is a differential current output. It needs to connect an LM358 at its output terminal to form an external conversion circuit to convert the current value into voltage, get the reverse voltage output. The single-chip microcomputer outputs an 8-bit digital quantity from the P0 port, which is input to the D/A module. The DAC0832 is powered by 5V voltage, and the resolution is 5256≈0.02V. Because it outputs a negative voltage, when the digital quantity increases by 1, The output of the D/A module increases by -0.02V.The amplifying module consists of an operational amplifier LM358 and resistors R2, R3, and R4 to form a 2.5-fold inverting amplifier, which reversely amplifies the output of the D/A module by 2.5 times. Every time the voltage adjustment button is pressed, the digital quantity will increase by 2, and the output of the D/A module will increase by -0.04V. After reverse amplification by 2.5 times, the output voltage will increase by 0.1V, realizing a step of 0.1V. And because the output range required by the voltage is 0 ~ 10V, the range of digital input is 00000000 ~ 11001000, the range of DAC0832 output is 0 ~ -4V, and the resolution meets the requirements. By changing the digital output of the P0 port of the single-chip microcomputer through the keys KEY1 and KEY2, the output voltage can be adjusted from 0 to 10V.2.2 Current amplification moduleThe design of the power supply has a maximum output current of 500mA, so after the signal is output from the amplifier circuit, it must pass through the current amplifier circuit to make the current reach the design standard. The output value of the amplification module is input into the current amplification module from the adjv port, and output from the UO port to obtain the final output value. The current amplification module is composed of operational amplifier LM358, high-power transistor 2SD1677, and resistors R5, R6, and R7. A high-power triode is used to form an emitter follower, powered by a 15V voltage, and the current is amplified under the condition of voltage following. In the selection of triode, since the maximum voltage of UCE is 15V, the maximum current is 500mA, and the maximum power is 7.5W, the maximum power dissipation PCM of the selected triode should be greater than 7.5W. After considering the heat dissipation factor and leaving a margin, this design selects the triode 2SD1677 with a PCM value of 100W.2.3 Sampling module and A/D moduleIn order to ensure the accuracy, it is necessary to sample the output voltage value and then perform A/D conversion, and compare it with the preset value output by the microcontroller to form a closed-loop system with negative feedback. The output voltage forms a voltage divider resistor through R8 and R9, and then passes through an LM358 operational amplifier to form a voltage follower and then enters the A/D module. The A/D circuit adopts STC12C5A60S2 single-chip built-in 8-bit A/D module, the reference voltage is 5V, and compares the converted digital quantity input to the single-chip with the output preset value.2.4 Bluetooth module and voice moduleThis design uses the HC⁃05 Bluetooth module to realize the Bluetooth remote control voltage function. Set the Bluetooth module to work at a baud rate of 9600b/s, and set it to work as a slave, and connect it to the serial port 1 of the microcontroller. The user can send data to the HC-05 module after connecting with a device with Bluetooth function such as a mobile phone; the HC-05 module then transmits the data to the MCU through the serial port to change the digital output of the MCU, thereby realizing Bluetooth control output voltage value.The voice prompt function is realized through the SYN6288 voice module. The SYN6288 voice module is packaged in SMD SSOP, small in size, connected to the host computer through the serial port, and receives the text sent by the serial port to realize the conversion from text to Chinese voice. SYN6288 has a built-in push-pull DAC and a speaker interface, which can directly drive the speaker for sound broadcasting. In this design, the SYN6288 module is connected to the serial port 2 of the microcontroller. When adjusting the output voltage, the MCU transmits the adjusted voltage value in the form of a string to the SYN6288 module through the serial port, and the module transmits the Chinese voice prompt to an 8Ω, 0.5W speaker for playback.3. Software Design of Bluetooth CNC DC Voltage SourceThe software of this power supply is written in C51 language. The system initializes first, and then judges whether the Bluetooth has received the value, and if so, changes the value of outv and outputs it; if the Bluetooth does not receive it, then judges whether the button is pressed, and if the button is pressed, changes the value of outv to output. Assign the output value sample to setv, compare whether the value of setv and outv are equal, if not, adjust the value of setv and output, and then perform sampling comparison until the value of setv is equal to outv.4. Bluetooth CNC DC voltage source system testInstall the SPP Bluetooth serial port debugging APP in the MOTOX smartphone of the Android system, and after connecting with the Bluetooth module of the power supply, use the SPP Bluetooth serial port debugging APP to adjust the value of the output voltage. Take 10 values from 0 to 10V for measurement, and use a digital multimeter VC9860+ as the measuring instrument to measure the voltage value at both ends of the load.During the test, whenever the preset voltage value is changed, the voice module can correctly broadcast the changed voltage value. The test results show that the output of the voltage source meets the output requirements of 0-10V, the output is accurate, the output response is good, and the function of bluetooth remote control of the output voltage is realized.epilogueThis paper introduces a design scheme of a digitally controlled DC voltage source based on the STC12C5A60S2 microcontroller. The voltage source adopts a closed-loop system with high output precision and compact structure. The value of the output voltage can be adjusted remotely through a Bluetooth device, and it has a Chinese voice prompt function. After testing, when the power supply is used to provide voltage to the load, the output response is good and the error is small, and it can be used in experimental teaching, scientific research, automatic measurement systems and other fields, and has broad application prospects.The above is the design technology of Bluetooth CNC DC voltage source with Chinese voice prompt function introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-11

2023

Bluetooth Device Test Solution

Bluetooth device testing is carried out on the basis of Bluetooth product technical specifications, including interoperability testing, conformance testing, etc. The Bluetooth device test should first carry out the formulation of the test plan, and then carry out operations such as protocol consistency, underlying hardware modules, and interoperability tests.1. Explanation of Bluetooth test modeThe purpose of testing Bluetooth devices is to ensure the final experience of excellent users, realize the optimal functions of Bluetooth devices, calibrate and test the performance of subsystems and components in Bluetooth devices, test the main environment and screen out defects. materials to ensure the quality of Bluetooth devices.According to the bluetooth technical specification, the definition of the application specification and the formulation of the test mode of the protocol are respectively carried out, such as the serial port emulation protocol, the service discovery protocol, etc. According to the specific female-public mode, each layer of protocol under the operation coordination mechanism is set for each functional element, and the entire Bluetooth protocol system is divided into three levels: the middle layer, the bottom layer, and the high-end layer, which are respectively the bottom hardware module and the middle protocol layer software. modules and high-end applications.Among them, the intermediate protocol layer includes adaptation protocol and logical link control, the underlying hardware part includes baseband, link management layer and wireless frequency hopping, and the high-end layer includes the application framework composed of telephone communication protocol, serial emulation protocol, and service discovery protocol. The test of the underlying hardware module function is particularly important, mainly through the compatibility test of the wireless baseband layer and the establishment of a test mode.The Bluetooth device test module includes the test device and the device under test, and builds a piconet. The test process is fully controlled by the master device. The device can use DUT as the device for Bluetooth transmission and reception, and use the additional measurement device TESTER as the system composition. The test process is: initialize the independent baud rate, click start, disconnect the serial port, receive data, and start to execute the command to test the Bluetooth device.In the test, the activation was performed locally using the wireless interface, the software ran the wireless interface, and the hardware took care of the activation. When the DUT is commanded to perform the activation operation, TESTER enters the test mode and issues a link management protocol command. After the activation command is received, it enters the test mode and the DUT returns to complete all standard operations. For the unfinished LMP-AC-CEPTED activation command, the software interface can be used to continue the activation operation until the connection with the TESTER is established, and then the paging scan and inquiry scan can be performed through the DUT.After the control operation of the control interface is performed using the LMP command, the test is passed. At this time, the DUT has not been standardized, but the hardware interface still exists, and the Bluetooth device does not need to execute the command in the test mode. After returning the LMP-NOT-ACCEPTED instruction, the DUT enters the test mode. After receiving the control instruction, the LMP instruction and processing power control are allowed to appear, and the standard program is used for testing. The power can be debugged during the process. By exiting the test mode, the instruction Set in the scheme to force the DUT out of the test module.The test scheme of the Bluetooth device includes the POLL grouping at the sending end, the periodic transmission of the piconet composed of TESTER, the testing of the sending end and the test grouping in the DUT unit, which works as the master unit, and the test device uses the TX time slot to perform the sending operation. The POLL group control command is used to operate, and the TX time slot is used to operate the unit. After the sending command is started, the unit can pre-define the interval through the unit wheel and set it to a fixed value, so that the device under test can send data regularly.The pseudo-random sequence refers to the fact that the shift register uses a uniform sequence as the random sequence of the transmission packet, the longer zero sequence is 8, and the sequence becomes 511 bits. The descending frequency hopping sequence uses the complete fast wireless test to perform five timing frequency hopping in the frequency range, and the channels are 0, 23, 46, 79, and 95 respectively. The bit pattern is sent and stopped in the form of a pseudo-random code, starting from a sequence of 1, alternating 1010, alternating 1111, 0000, 1111, 0000, and the sequence can also start from 0. Frequency selection includes European and American frequency hopping, Japanese frequency hopping, Spanish frequency hopping, French frequency hopping, and frequency hopping in descending order.The format of the test packets is grouped using forward error correction codes, including AUX1. HV3, DH1, 3, 5. Divided into payload length format, packet format, etc. When sending in test mode, TESTER defines the payload length through appropriate settings, and the control of transmission parameters meets the requirements of the baseband specification, and test sending can be performed.Switching between different frequency settings, after receiving a new frequency band message, DUT starts to switch after receiving the message.For power control, use the conventional LMP command to test and control the adaptive power, use the drunk power for transmission, and increase or decrease the power according to the received command.After decoding the device under test, the conventional baseband grouping method is used for transmission between the next TX time slot, and the effective load is carried out in the TX time slot loopback test, and the pseudo-random sequence code of enabling or stopping is sent back, and the same grouping is used Then add noise in the test equipment.If the test mode control information is included in the packet, the instruction will not be executed and will not be returned to other packets when other LMP instructions are ignored. It is allowed to use the error correction code FEC for encoding and decoding in the forward error correction processing test. The grouping of test equipment uses bit error rate for forward error correction testing.In the case of CRC invalidation, the payload is used for grouping, and the packet carrying the CRC can be returned by the payload. If the header verification fails, the ARON can return a NAK by using a NULL packet containing the ARQN bit, and may not respond if the synchronization header is not detected.2. Bluetooth test control interfaceThe Bluetooth technical specification includes two documents, the application framework and the core protocol. The former specifies the definition of each layer of Bluetooth communication protocols, and the latter specifies the product applications implemented by the protocol.All Bluetooth components are tested with the conformance test protocol, and the protocol of the object under test is tested in the peripheral product. After the high-level device UT implements the underlying functions, the protocol is verified and implemented through testing. In order to avoid the change of each measured object and test system due to different situations, the mandatory test method of the standard control interface can be used to access the test equipment, and the method of uniformly testing the high-level interface can be used, and the IUT uniformly supplied by the manufacturer can be used. The adapter performs hardware and software operations.In the verification of the baseband layer, logical link control and adaptation protocol interface, and link management layer protocol, the interface between the test equipment and the SUT used includes: TCI-L2CAP interface, which can be used after verification by the SUT , events and commands can be defined through the service interface, which can be converted into messages in the same format as commands and HCI events. The TCI interface is used for the host control interface, and is used as the interface of the test system through the verification of the link management layer and the link control layer. The test system realizes event access with the upper layer by sending HCI event access commands and HCI commands. The test equipment used is located in the transport layer channel, including physical channel and software channel, because the manufacturer is responsible for the operation of the software and sends data to the device.3. Bluetooth protocol stack conformance testThe test is checked and given with the entity through the intrinsic form of the protocol. The internal specifications are consistent with each other, and can only be tested after passing the description of the specification and the detection of the output form.The structure of the L2CAP conformance test includes three components: the conformance test system, the test control software and the tested object. The execution test system is connected through the test control interface in the bluetooth device, and the test control software performs an air interface to the bluetooth transmitting device in the object under test. The recommended physical transport layer of TCI is the specified transport layer of HCI, including RS232, UART and USB. The test system sends L2CAP system commands to the object under test. After the object under test receives the command, the upper layer of the test system drives through the physical bus driver and the L2CAP driver, and the underlying object under test implements L2CAP data after processing. grouping.The test control software includes three components: L2CAP firmware, adapter and physical bus. The test control software is adapted through the interface. The data in the test control software is sent by the physical bus. After reaching the upper level of the test system, the data is received, and the firmware encodes and decodes the data. The interface in the adapter performs IUT adaptation, and finally realizes the test of the object under test according to the software of the Bluetooth master protocol.SummarizeWith the rapid development of information technology, new types of smart terminals integrate computing and communication. New devices represented by smart terminals and smart phones have gradually replaced traditional desktop computers and notebooks, which are smaller in size, lower in power consumption, and With a variety of communication means, such as Bluetooth technology, for information interaction. As one of the main short-distance and low-power wireless communication technologies, Bluetooth technology has been widely used in the field of transmission and information exchange, and has become the cutting-edge technology of wireless communication. The purpose of designing the Bluetooth test program is to realize mobile Wireless connection between equipment and fixed equipment, and achieve the goal of low cost and simple construction. This paper systematically analyzes the implementation process of the bluetooth test scheme through the elaboration of the conformance test method of the bluetooth protocol and the test mode of the bluetooth device.The above is the test solution technology of Bluetooth devices introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-10

2023

Bluetooth Smart Barricade System

Intelligent roadblock system based on bluetooth control technologyWith the increase of vehicles, urban traffic problems are becoming more and more prominent. Roadblocks are an essential facility for traffic management. Traditional roadblocks are manually arranged and moved. Staff are in danger of being hit by vehicles. The use of intelligent roadblock systems can avoid being hit by cars. Hazardous, reduce manual labor. With the continuous development of smart cities and smart transportation, my country's research in the field of unmanned vehicles has made great progress. During the testing process, there are still uncontrollable dangers. In the road link, the intelligent roadblock system is adopted to remotely control the transformation of the roadblock formation to prevent danger and protect the personal safety of the participants.1. Overall design of intelligent roadblock systemConsidering the functional requirements and cost control used in the competition, in this design scheme, the intelligent roadblock is mainly divided into two parts: the control unit and the wireless module. A relatively stable remote control design is adopted, and a dedicated remote control is designed as the control terminal. The STM32F103 series single-chip microcomputer is used as the main control unit of the intelligent roadblock and the remote control, and the wireless transmission module adopts the master-slave integrated Bluetooth chip HC-05. Due to the large loss of smart roadblocks in the competition, in order to ensure the loss of the competition, there must be a sufficient number of smart roadblocks. This design realizes cost control on the basis of meeting the functional requirements and quantity requirements of the competition.1.1 Intelligent roadblock hardware circuit designFrom the perspective of mechanical structure, the intelligent roadblock is divided into an upper roadblock and a lower movable wheeled base plate, and the road block and the base plate are fixed together with screws. There are two driving wheels and one driven wheel under the bottom plate, each of which is equipped with a DC motor, and the bottom plate is fixed with a motor drive module L298N, a core control unit STM32, a Bluetooth chip HC-05, and a 7.2V rechargeable lithium battery. The remote control uses STM32 as the main control unit, 4*4 matrix membrane switch as the remote control button, and 5V dry battery as the power supply.The L298N integrates two high-voltage and high-current full-bridge drivers of the H-bridge, which can drive inductive loads; it adopts standard logic level signal control; it has two enable control terminals, allowing or There is a logic power input terminal for prohibiting the operation of the device, so that the internal logic circuit part can work under low voltage; the detection resistor can be connected externally, and the change can be fed back to the control circuit.The chip can drive a two-phase stepper motor or a four-phase stepper motor, or two DC motors. The L298N directly drives two DC motors, namely M1 and M2. Pins A and B are connected to 5V, the motor is working at the highest speed, the input signal terminal IN1 is connected to a high level input terminal IN2 is connected to a low level, and the motor M1 is rotating forward. The signal terminal IN1 is connected to a low level, IN2 is connected to a high level, and the motor M1 is reversed. Controlling M2 is the same way.1.2 Intelligent roadblock software designIn terms of software design, the main control unit we use is STM32, a 16-bit microcontroller with a clock frequency of up to 72MHz and a power consumption of 36mA, which has the advantages of powerful performance and ultra-low power consumption. It meets our design requirements and can stand by for a long time. After testing, it can stand by for 48 hours when not in use. Under continuous testing, it can work continuously for more than one hour, which fully meets our needs. After the power is turned on, the program performs initialization settings, and the smart roadblock works in the standby state. The Bluetooth module has been detecting whether it has received a control signal. After receiving the signal, the smart roadblock Bluetooth module sends the control signal to the smart roadblock control unit. Control the signal to make forward, backward, left turn, right turn actions to realize the movement of intelligent roadblocks and meet the requirements of roadblock formation changes.1.3 Smart Barrier Bluetooth DesignBluetooth is a wireless technology standard, which can realize data transmission between fixed equipment and mobile equipment. The HC-05 Bluetooth module used in this design can perform full-duplex communication with the STM32 series single-chip microcomputer main control chip, that is, the two can read and write each other. For example, when sending data from the Bluetooth module, the write terminal (TXD) of HC-05 is connected with the read terminal (RXD) of the MCU main control chip to realize communication; otherwise, the read terminal (RXD) of HC-05 and the MCU main control chip The write terminal (TXD) is connected. When connecting, you need to pay attention to the cross-connection of two pairs of read-write terminals, and the two need to share the same ground (this Bluetooth module has a total of 4 pins on the power terminal, and there is no need to connect them separately).The remote control and the smart roadblock communicate wirelessly through the Bluetooth module. The Bluetooth on the remote control side is set to the master mode, and the Bluetooth on the smart roadblock side is set to the slave mode. Different passwords are set for the two remote controllers, which can distinguish the two remote controllers from controlling two sets of smart roadblocks. According to the button pressing mode of the control terminal, different numbers of intelligent barriers will respond. After testing, the bluetooth chip we choose can reach an outdoor control distance of 20 meters, which can fully meet our design requirements.2. Design of the remote control end of the Bluetooth smart roadblock systemIn this project, a total of 50 intelligent roadblocks are designed, and each group of 10 is numbered A 0-9, B0-9, C0-9, D0-9, E0-9. The program assigns different numbers to each roadblock The setting enables the smart barricade to discern whether to respond to a control signal. On the track, different numbers of smart roadblocks can be adjusted to realize free formation changes of roadblocks, providing a good competition environment for the China Smart Car Future Challenge.Considering that the roadblocks are divided into two rows during the competition, we designed two remote controllers to control 25 smart roadblocks respectively, and the two groups correspond to two rows of roadblocks. The 0-9 number keys of the matrix membrane switch correspond to the individual numbered 0-9 intelligent roadblocks; the # key corresponds to the all-select function (25 sets are all selected), and in the all-select mode, the number 0 is selected to correspond to the remote control of the corresponding set All numbers under the control are intelligent roadblocks numbered 0; A, B, C, and D keys correspond to forward, backward, left turn, and right turn functions; among them, A, B, and C are multiplexed keys, and correspond to A, B, and E (Five of them) Groups have the function of selecting all groups, the * key is used as a multiplexing signal distinguishing key, when A, B, C, D are used as forward, backward, left turn, right turn functions, you need to press * at the same time word key.The matrix switch is pressed to provide a low-level signal, and the main control unit sends a signal through Bluetooth to control the intelligent roadblock. When controlling the smart roadblock to move forward, backward, turn left, or turn right, keep pressing the * key and one of the keys A, B, C, and D to realize the continuous response of the smart roadblock, and release the button to stop the response of the smart roadblock. Since the control mode is designed with multiple combinations of single selection and multiple selection, it can work in the most suitable control mode according to needs.3. Practical and innovative concept of intelligent roadblock system designThe main reasons for the applicability of this barricade are:(1) Simple mechanical structure. A chassis with universal wheels and driving wheels is fixed at the lower part of the barricade for the control and movement of the barricade. The mechanical structure is simple and stable, and has strong applicability and manufacturability.(2) Easy-to-operate remote control method, the button design of the remote control terminal of the intelligent roadblock is simple and convenient, which can realize multiple control options in different combinations, easy to adjust the formation, and can be controlled from a long distance, which can be suitable for arriving in different competition vehicles in time during the competition Adjust and transform the formation before to form a freely transformable game level.(3) Simple intelligent roadblock design, only adding chassis, battery, motor, drive module, central control unit, bluetooth module to the original roadblock design, simple design, controllable cost, can meet the competition requirements, suitable for competitions possible risk of accidental damage.SummarizeThe intelligent roadblock system introduced in this article has a simple mechanical structure, easy-to-learn remote control method, simple design and stable function of the intelligent roadblock, and can realize remote control or on-site remote control of the intelligent roadblock under different road conditions. The simple and practical design of the smart roadblock is suitable for various scenarios such as large parking lots, office buildings, road construction, traffic diversion, etc. It solves the problems of physical labor and personal danger in traditional roadblock deployment, and helps solve urban traffic problems. Its low cost and stable functions can realize commercial production and use.The above are the details of the intelligent roadblock system based on Bluetooth control technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.

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