This chapter gives a detailed description of the I2C and its configuration for use. The system chip has an integrated I2C interface, which is mainly used to implement the exchange of data between two devices. The I2C bus is a serial bus consisting of a data line SDA and a clock SCL to send and receive data. Bi-directional transmission is performed between devices with a maximum transmission rate of 400kbps.
The I2C controller integrated in the Loongson 3A5000 can act as either a master or a slave device, and the two modes are switched between by configuring internal registers.
As a slave device, it is only used to read the internal temperature of the chip, and the address of the slave device is specified by register SLV_CTRL[6:0].
The physical address base address of the I2C0 controller register is 0x1FE00120.
The I2C1 controller register physical address base address is 0x1FE00130.
The specific internal registers are described below.