Recently, TI released the fourth generation low-power Bluetooth SoC-CC2340. This product embodies TI's more than 20 years of radio frequency experience and has optimized design in terms of cost, size and performance. It is currently the most valuable low-power low-power SoC on the market. One of the Bluetooth SoCs.
TI CC2340 SoC uses a 48 MHz ARM Cortex-M0+ MCU, up to 512 KB flash memory and 36 KB memory, providing excellent computing performance and supporting OTA upgrades, which can reduce post-maintenance costs.
CC2340 supports low-power Bluetooth 5.3, Zigbee, proprietary 2.4 GHz, and is backward compatible with Bluetooth 4.2/5.0/5.1. It is suitable for use as RSSI/Bluetooth AoA positioning tags.
CC2340 standby current <0.7 uA (memory retention), 1s BLE connection interval power consumption is only 6 uA, extremely low power consumption TX output power is -20 to +8 dBm, RX receiving sensitivity -96 dBm@1 Mbps, low power It has excellent power consumption and radio frequency performance, which can improve battery life and is suitable for low standby power consumption applications in automobiles.
The CC2340 is small in size. The CC2340R5 version is available in a 5mm×5mm QFN40 package, and the CC2340R2 version is available in a 4mm×4mm QFN24 package. The small size and integrated balanced-unbalanced transformer facilitate deployment in space-constrained applications.
CC2340 has an operating temperature range of -40ºC to 125ºC, which can provide stable connection in complex and harsh working environments. An AEC-Q100 automotive version will also be provided in the future to meet the needs of automotive applications.
CC2340 supports AES 128 encryption hardware accelerator, providing high security.
As a third-party IDH of TI, Shenzhen Xinchida Technology Co., Ltd. combines the characteristics of CC2340 SoC and launches a BLE PEPS digital key solution based on the CC2340 series Bluetooth module. It uses BLE low-power Bluetooth to connect mobile APPs and cars to achieve keyless entry. , keyless start, as well as functions such as unlocking, locking, controlling the trunk, finding the car, and authorizing the car to be borrowed.
Figure 1 Xinchida BLE PEPS solution
With the improvement of people's living standards, the number of private cars is increasing year by year, and users' requirements for cars are becoming more and more diverse. In addition to basic power, comfort, and safety, new demands such as convenience and interactivity are also are increasingly valued. At the beginning of the 21st century, the Passive Entry and Passive Start (PEPS) system was proposed. This technology is based on high and low frequency two-way communication and aims to simplify the tedious unlocking and starting operations of users during vehicle use. Although the development of traditional high- and low-frequency PEPS solutions is relatively mature, users must be equipped with and carry a dedicated smart key. With the introduction of the concept of the Internet of Things, the Internet of Vehicles technology has been valued by domestic and foreign automobile manufacturers for its ability to realize information interaction between people, vehicles and roads. The low-power Bluetooth PEPS technology (Bluetooth Low Energy) of the smart key is replaced by the user's smart terminal. Passive Entry and Passive Start (BLE PEPS) was proposed as an emerging technology solution to replace traditional high and low frequency PEPS.
Compared with traditional high and low frequency PEPS systems, low-power Bluetooth PEPS systems have obvious advantages:
1► Smartphones are popular, and smart phones all contain Bluetooth modules, which have natural conditions for use;
2►The Bluetooth module is small in size, and low-power Bluetooth uses wireless communication to get rid of the limitations of cables. Therefore, the installation position of the Bluetooth module can be selected according to the manufacturer's model, and it is more practical;
3► The cost of low-power Bluetooth PEPS system is lower, and the price of Bluetooth module is lower;
Based on the above advantages, the BLE PEPS solution can provide more intelligent and scalable development prospects for PEPS technology in the Internet of Things era.
►►►System solution introduction
The BLE PEPS system includes two functions: BLE keyless entry and BLE keyless start. BLE keyless entry means that the user pulls the door handle/presses the door open button, and the BLE PEPS system automatically searches for the Bluetooth smart key within a certain range of the car door. If a legitimate Bluetooth smart key is found, it automatically performs the unlocking function. BLE keyless start means that when the user starts the vehicle, the BLE PEPS system automatically searches for the location of the Bluetooth smart terminal. If it is determined that the legal Bluetooth smart key is in the car, the vehicle can be started.
The positioning and ranging accuracy of BLE PEPS is between half a meter and a meter. The relatively low-end Bluetooth PEPS solution uses RSSI ranging to achieve positioning accuracy of 1-5 meters. The mainstream Bluetooth PEPS solution uses Bluetooth AoA technology to achieve half-meter positioning.
In Bluetooth version 5.1, the AoA (Angle of Arrival algorithm) function, which is meaningful for BLE digital keys, is added to support more accurate positioning. In the Bluetooth AoA positioning solution (as shown in Figure 3), the transmitting device such as a mobile phone regularly sends special signals. The vehicle body Bluetooth antenna receives the special signals through an antenna array and sends the information to the Bluetooth main module to calculate the location information of the transmitting device. This solution can more accurately determine the location (distance and direction) of the transmitting equipment, with an accuracy of about 0.5 meters.
Figure 2 Bluetooth AoA positioning
The number of Bluetooth antennas is related to the Bluetooth positioning accuracy requirements. If the Bluetooth accuracy is required to be higher, the number of antennas is required. For example, the status of conventional 1+3, host module + 3 Bluetooth antennas is one on each side of the left and right doors. , there is one in the trunk, which can basically cover more than 90% of the positioning in the car. Passenger cars will be implementing the 1+N solution starting in 2022. The following figure shows the current Bluetooth antenna configuration of common passenger cars, as shown in Figure 3.
Figure 3 PEPS Bluetooth antenna configuration
The system calculates the position of the Bluetooth smart key based on Bluetooth positioning. It mainly consists of a BLE main module (responsible for positioning algorithm, communication with the vehicle, communication with the BLE antenna, BLE signal transmission and reception, etc.), several BLE antennas (at least 3 or more, It communicates with the BLE main module, transmits and receives BLE signals, etc.) and a Bluetooth smart key.
After the BLE main module detects the Bluetooth smart key, it actively wakes up the BLE antenna. The BLE antenna communicates with the Bluetooth smart key to obtain the phase difference corresponding to the Bluetooth smart key. The BLE antenna sends the obtained information to the BLE main module, and the BLE main module calculates the position of the Bluetooth smart key based on the phase differences corresponding to multiple Bluetooth smart keys.
The BLE main module sends the location information of the Bluetooth smart key to the body domain controller. The body domain controller performs unlocking or one-key start operations on the vehicle based on the location information of the Bluetooth smart key and combined with the user's operations.
The solution uses Xinchida Technology’s Bluetooth module RF-BM-2340B1 based on CC2340 SoC as the Bluetooth antenna. The module is cost-effective, ultra-low power consumption and high radio frequency performance. It adopts 1+3 configuration and can achieve 50cm positioning accuracy. Advantages of the solution as follows:
1►Low power consumption, high performance, high security;
2►Mobile phone is the key, users have more peace of mind;
3► APP intelligently manages cars, meeting the requirements of modern smart cars;
4► Provide hardware and software technical support to shorten the development cycle;
With the development of the Internet of Vehicles, BLE has become a technology that has attracted much attention in the market due to its high popularity, unified standards, complete ecosystem and relatively low price. BLE PEPS provides user needs for keyless entry and keyless start with a smartphone. Combining BLE PEPS with traditional PEPS can achieve half-meter positioning accuracy and provide a better user experience. With the subsequent launch of the CC2340 automotive-grade chip, CC2340 is bound to shine in the PEPS field.
About Xinchida
The R&D team of Xinchida Technology has many years of experience and technology accumulation in the wireless communication module industry, and is committed to providing customers with high-quality wireless radio frequency solutions and product services. As a third-party IDH of TI in the United States, Xinchida Technology will continue to promote the market popularization and technological progress of Bluetooth and multi-protocol products, provide all-round support for TI's fourth-generation wireless SoC----CC2340, and accelerate its success in the market. promotion and application.