SPI MISO outputs sclk

9P 9215 development board
DEL 5.7.0
target device running LINUX:


I am running the test C code for SPI with the spidev1.0 device file.

Writing to devices works as I can control the I/O pins of the MCP23S08 I/O expander.

However, no matter what data I send out the MISO(RXD) pin of the developmnet board outputs the clock.
It does this even if I have the MISO(RXD) pin disconnected from the slave.

Any help is greatly appreciated.


Which SPI device are you trying to use?
Make sure that you have configured SPI properly in kernel/rootfs configuraton.

Refer Digi ESP > Help > Help Contents > Digi ESP for Embedded Linux > 9. Devices and Interfaces 9.25. Serial Peripheral Interface (SPI)


It turns out that the MISO and SCLK are shorted together on the dev board.