SPI not working

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
1

Hi ! I’m trying to setup spi1 in order to control a small screen.

So I enabled spi1via jetson-io. Then, after reboot I launched sudo modprobe spidev to load the kernel module. Then I downloaded https://raw.githubusercontent.com/torvalds/linux/v4.9/tools/spi/spidev_test.c and compiled it to test the spi. I connected pin 19 and 21 using a cable and ran the following:

(base) ninon@neurorack:~$ ./spidev_test -D /dev/spidev0.0 -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  | ................................
(base) ninon@neurorack:~$ ./spidev_test -D /dev/spidev0.1 -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  | ................................
(base) ninon@neurorack:~$ ./spidev_test -D /dev/spidev1.0 -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  | ................................
(base) ninon@neurorack:~$ ./spidev_test -D /dev/spidev1.1 -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D  | ......@....�..................�.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  | ................................

It doesn’t seem to work… I suspect pinmux misconfiguration since it’s already what caused my problem with i2s but I can’t really find how to check or correct that !

You can find my .dtb here: I2S not working on Jetson Nano Devkit - #6 by valentin.lageard.pro

Thanks !

2

Hi,
Please refer to the steps of doing loopback test on Jetson Nano developer kit and give it a try:

Jetson/L4T/peripheral/ - eLinux.org

3

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