The MB-SMARC-2 has two SPI interfaces. They are available on the extension headers and can be tested with a loopback test.
In order to determine the correct SPI interface name, the following command can be used:
ls /dev | grep spi
| Interface | Linux filesystem |
|---|---|
| SPI0 | spidev1.0 |
For the loopback test, SPI_MOSI and SPI_MISO need to be bridged:
On MB-SMARC-2 the corresponding pins are pins 15 and 16 on X24.
echo -n -e "\x01\x0F" | spi-pipe -d <spi interface> -s 10000000 | hexdump (e.g. echo -n -e "\x01\x0F" | spi-pipe -d /dev/spidev1.0 -s 10000000 | hexdump)