Tool/software: Linux
When we tested the SPI function, we found that the MOSI signal in the transmission process will produce a drop,the waveform as shown below:
The specific software configuration is as follows, through the MOSI output 90h:
Uboot pinmux is configured as follows:
{MCASP1_AXR8, (M3 | PIN_INPUT_PULLDOWN)}, /* mcasp1_axr8.spi3_sclk */
{MCASP1_AXR9, (M3 | PIN_INPUT_PULLDOWN)}, /* mcasp1_axr9.spi3_d1 */
{MCASP1_AXR10, (M3 | PIN_INPUT_PULLDOWN)}, /* mcasp1_axr10.spi3_d0 */
{MCASP1_AXR11, (M3 | PIN_INPUT_PULLUP)}, /* mcasp1_axr11.spi3_cs0 */
{MCASP1_AXR12, (M3 | PIN_INPUT_PULLUP)}, /* mcasp1_axr12.spi3_cs1 */
Kernel configuration is as follows:
&mcspi3 {
status = "okay";
ti,spi-num-cs = <2>;
spidev0 {
compatible = "spidev";
reg = <0>;
spi-max-frequency = <50000000>;
};
spidev1 {
compatible = "spidev";
reg = <1>;
spi-max-frequency = <50000000>;
};
};
