I’ve got two Jetson Nanos, and can’t get the SPI bus to work on either of them (presumably for the same reason on both).
If I run
ls -lah /dev/spidev* on either one, I can see that there are 4 SPI devices I can talk to (bus 0 or 1, chip select 0 or 1 for each), and all of them are readable/writable by users in the
gpio group, which is a group that I am in. I can also run
lsmod | grep spi and get back
spidev 13282 0. That last 0 is a little odd because it indicates that nothing is using the module, but at least the module exists and is ready to go if something wants to use it.
I plugged pin 19 into pin 21 on the “jetson-io-base-a” breakout board, which is supposed to be plugging MOSI into MISO on SPI bus 0. I then ran
spidev-test from GitHub - rm-hull/spidev-test, but I only receive null bytes, indicating that the SPI bus isn’t working properly (it’s not receiving the data it’s sending despite the pins being jumped together).
I’ve tried running
sudo /opt/nvidia/jetson-io/jetson-io.py, but on one of my jetsons, it exits immediately with no output, and on the other it lets me configure camera-related stuff but has no options for configuring SPI or other GPIO pin things. I suspect that this is the thing that’s going wrong, that if I could successfully get
jetson-io.py to enable the SPI pins, things would improve. On the other hand, given that the
/dev/spidev* devices already exist, maybe the SPI bus is already set up and I don’t need to worry about
jetson-io.py at all, and the problem is elsewhere.
Any idea what’s going wrong? What should I try next?