I2C bus learning (IV)--reading and writing process

Writing process

     When the microcontroller performs a write operation, it first sends the 7-bit address code of the device and the write direction bit "0" (a total of 8 bits, i.e., one byte). After sending, the SDA line is released and the ninth clock signal is generated on the SCL line. After the selected memory device confirms that it is its own address, it generates a response signal on the SDA line as a response. After receiving the response, the microcontroller can transmit data.

    When transmitting data, the microcontroller first sends a byte of the first address of the storage area of ​​the device to be written. After receiving the response from the memory device, the microcontroller sends each data byte one by one, but waits for the response after each byte is sent. When the data to be written is transmitted, the microcontroller should send a termination signal to end the write operation. The data format for writing n bytes is:

Reading process

     The microcontroller first sends the 7-bit address code and write direction bit "0" ("pseudo write") of the device. After sending, it releases the SDA line and generates the 9th clock signal on the SCL line. After confirming that it is its own address, the selected memory device generates a response signal on the SDA line. Then, send another byte of the first address of the storage area of ​​the device to be read. After receiving the response, the microcontroller repeats the start signal and sends the device address and read direction bit ("1"). After receiving the device response, the data byte can be read. The microcontroller must reply with a response signal for each byte read. When the last byte of data is read, the microcontroller should return to "non-response" (high level) and send a termination signal to end the read operation.