The I2C bus in the automotive sector
What is I2C?
I²C (Inter-Integrated Circuit) is a 2-wire serial data bus developed by Philips Semiconductors (now NXP Semiconductors) in 1982. I2C is a simple bus system and is used today in almost every system with peripheral devices.
Where is I2C used?
It is mainly used internally in the device for communication between different parts of the circuit, e.g. between a controller and peripheral ICs. An example of this is a temperature sensor microcontroller and EEPROM. The microcontroller reads the sensor and stores the data on the EEPROM. The complete data exchange is done via I2C.
What are the problems with I2C in the automotive sector?
Due to the presence of only two wires, the handling of the addressing and acknowledgement effort is very complex. The I2C bus is unsuitable for meter-long transmissions, especially in the automotive sector, where there are also many interfering influences on the signal transmission, such as the ignition or the alternator. More suitable communication protocols such as CAN or RS-485 are preferred for internal vehicle networks.
I2C ICs for the automotive sector
Since the I2C devices like EEPROMs have to withstand more difficult environmental influences and higher requirements, various IC manufacturers offer devices specially made for this purpose, which have a higher temperature tolerance and are less susceptible to faults.
Automotive IC example
An example of an IC manufactured specifically for the automotive sector is the AT24HC04B EEPROM from Microchip (ATMEL), whose temperature operating range (Class 1) has been extended and is particularly energy-efficient. Temperature range class 1 : -40 ° C to 125 ° C.
