Design and mass production programming of car keyless control system

Most electronics practitioners are familiar with "watchdog", which is a technical means to prevent computer programs from entering an infinite loop and jumping out. This article will show you a car "watchdog" that is different from the traditional sense, and look at the design and mass production burning of the car keyless control system.

From the perspective of the global automobile market, the industry has maintained an overall growth trend since 2005, with automobile sales increasing from 65.9576 million in 2005 to 89.6780 million in 2015, with a compound annual growth rate of 3.12%. With the increase in the number of cars, automobile anti-theft technology has received widespread attention, which will be introduced in detail below.

The development of automobile anti-theft systems has mainly gone through three stages: traditional mechanical key systems, remote control key systems, and keyless intelligent systems.

1. Traditional mechanical key system

 This method achieves the purpose of anti-theft through mechanical principles. Turning the key opens the door and turning the key to start the engine. It has low technological content, insufficient anti-theft performance, and key information can be easily copied. This method is rarely used alone now.

Figure 1 Automobile mechanical key

2. Remote control key system

The remote control key system is an upgrade of the traditional mechanical key system. It uses wireless radio frequency technology to remotely control the opening and locking of the car. Compared with the traditional mechanical key, the remote control key must be doubly identified by the key and the chip before the car can be started. It has the characteristics of high technological content and sufficient safety performance. The chip has various software and hardware encryption matching algorithms, which increases the difficulty of cracking the system.

Figure 2 Car remote control key

3. Keyless Intelligent System

At present, many models are equipped with keyless systems, which are intelligent systems that automatically lock and open doors. When the owner leaves the car, the sensor inside the car cannot sense the presence of the key and will automatically lock the door. When the vehicle is in a locked state, it will continuously send out signals. When the smart key appears within the signal range, there will be a response to complete the number-checking behavior.

The smart system can not only be used to lock the car, but also to pre-start the air conditioner and other smart actions, bringing us a more comfortable car experience. The emergence of keyless smart systems for cars not only facilitates car owners, but also improves the safety performance of cars.

Figure 3 Car keyless control system

After reading the above introduction, do you think the keyless control system is very advanced? So what kind of powerful chip is used to design this high-tech product? Please see the detailed analysis below.

The PCF79xx series chips are products launched by NXP Semiconductors in the field of car anti-theft, which promotes the car anti-theft system to a more advanced stage. The chip has extremely low power consumption, ensuring the endurance of the system. It integrates UHF transmitter and LF frequency transceiver chips, and has various software and hardware encryption algorithms, such as Hitag2, Hitag2-E, Hitag-AES, etc., to ensure the security of data communication. And the 32-bit unique identity identification code (ID) is solidified internally, and the encryption algorithm is bound to the ID, so as to achieve the effect of being impossible to crack. As shown in the figure below, it is the chip ID information read by the P800 programmer.

Faced with the rapidly growing automobile market, automobile safety issues have attracted widespread attention from the society, and the demand for anti-theft systems is also increasing. To meet the market demand, ZLG Zhiyuan Electronics launched the P800 ISP online programmer, which can batch burn PCF79xx series chips, solving the batch demand problem of smart keys.