SPI Communication

1. SPI Features

SPI (serial peripheral interface). Below are some features supported by Linux 6.1 SPI driver:

  • Uses Motorola SPI protocol by default
  • Supports 8-bit and 16-bit
  • Software programmable clock frequency up to 50MHz
  • Supports SPI 4 kinds of transmission mode configurations
  • Each SPI controller supports one to two chip selects
  • Framework supports both slave and master modes

2. SPI Pins

TOOL
SPIPinFunction
MOSI19Master output / Slave input
MISO21Master input / Slave output
CLOCK23Clock signal line
CS024Chip select signal line 0
CS126Chip select signal line 1

Warning

spidev3.0 controls CS0

3. DTS Configuration

Enable spi in the device tree.

    &spi3 {
        status = "okay";
        spidev:spidev@0 {
                compatible = "rockchip,spidev";
                reg = <0>;
                spi-max-frequency = <10000000>;
                status = "okay";
        };
    };

4. Check SPI Device

Enter the following command on the board terminal to check if SPI device is generated.

TOOL