voxl_spi_init, failed to open /dev/spidev device: No such file or directory.

Alex Kushleyev

Another quick tip for testing SPI stuff. I found this useful:

https://github.com/rm-hull/spidev-test/blob/master/spidev_test.c

You can download this file to VOXL2, build it using

gcc -O2 spidev_test.c -o spidev_test

and then you can actually query the IMU on spi 3:

voxl2-mini:~$ ./spidev_test -D /dev/spidev3.0 -p "\x76\x00\xF5\x00"
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
RX | 00 00 00 47 ...

and from here we know that 0x47 is actually the value WHOAMI register of ICM42688 IMU

The data i am sending to the device is 4 bytes used to query the imu, as done here . the value 0xF5 = 0x75 | 0x80 which tells the IMU to send back the value of register 0x75

이광철

@Alex-Kushleyev

I will connect my spi device and let you know the results after testing.
Thanks for your help.

이광철

@Alex-Kushleyev

Hi.

I tested it by connecting my spi device to j10.
This spi device is working normally in voxl2.
My program for testing also operates normally with this spi device in voxl2.
However, when I test the spi device and test program on voxl mini, there is no response to the voxl_spi_write function.

Also, the test below is the same as before.
voxl2-mini:/dev$ qrb5165io-spi-test -d 14
There is no response to the qrb5165io-spi-test -d 14 command.

I need your help and thanks in advance.

이광철

@Alex-Kushleyev

I tested according to your advice.
This is the result of testing on my mini.

voxl2-mini:~$ cd /usr/bin
voxl2-mini:/usr/bin$ spidev_test -D /dev/spidev3.0 -p "\x76\x00\xF5\x00"
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
can't send spi message: Invalid argument
Aborted

이광철

@이광철

Alex-Kushleyev sorry.

voxl2-mini:~$ cd /usr/bin
voxl2-mini:/usr/bin$ spidev_test -D /dev/spidev3.0 -p "\x76\x00\xF5\x00"
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
can't send spi message: Invalid argument
Aborted

This test was my mistake.

Below are the final test results.
voxl2-mini:/usr/bin$ spidev_test -D /dev/spidev3.0 -p "\x76\x00\xF5\x00"
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
RX | 00 00 00 47 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ | ...G

Alex Kushleyev

@이광철 ,

Please note that qrb5165io-spi-test -d 14 is a test app that just tries to detect a specific IMU on the SPI port. If the specific IMU is not connected, the test will not be successful.

Are you able to read any data from your SPI sensor (using spidev_test -D /dev/spidev14.0 ... ? Can you share what your sensor is? You should look in the documentation of your sensor and it will tell you how to communicate with it. SPI protocol for reading / writing is specific to the device.

Also, don't forget about the gpio setting that needs to be made before using SPI 14 (voxl-gpio -w 67 1). this needs to be run after each reboot.

Alex

이광철

@Alex-Kushleyev

Please note that qrb5165io-spi-test -d 14 is a test app that just tries to detect a specific IMU on the SPI port. If the specific IMU is not connected, the test will not be successful.
Yes I know.

My spi device and test program works fine on volx2's J10.
Please refer to j10 in the url below.
https://docs.px4.io/main/en/flight_controller/modalai_voxl_2.html

Alex Kushleyev

@이광철 , do you still have any issue? Does spidev_test work with spi 14?

이광철

@Alex-Kushleyev

I tested it by connecting my spi device to j10.
This spi device is working normally in voxl2.
My program for testing also operates normally with this spi device in voxl2.

voxl_spi_init(SPI_BUS, SPI_MODE_0, VOXL_SPI_MAX_SPEED) is OK
but, there is no response to the voxl_spi_write function.

Alex Kushleyev

@이광철 , can you confirm that you are setting gpio 67 on voxl2 mini before testing spi 14?

이광철

@Alex-Kushleyev

Yes.
After executing voxl-gpio -w 67 1, run my test.

voxl-gpio -r 67
1

Alex Kushleyev

Hmm.. we will investigate.

modaltb

Hi @이광철

Sorry for missing guidance, I do think an alias is also needed like this:
https://gitlab.com/voxl-public/system-image-build/meta-voxl2-bsp/-/commit/e97a22de6b4e5582fc276a963b958d01a478d56b#999b45d40c8aafd81669d788073c2ea1315dac66_66_62

Also for this to work, I believe you will want to use the older devcfg.mbn file as well from SDK 1.0.0 as that has trustzone setup for SPI, and the new devcfg.mbn is setup for UART.

If trustzone isn't configured correctly I do think the kernel halts on bootup.

Flashing devcfg.mbn is like this, which is likely needed once alias is setup, to convert back to SPI from UART.

fastboot flash devcfg_a devcfg.mbn
fastboot flash devcfg_b devcfg.mbn

이광철

@modaltb

Hi.
I try a test on voxl-mini with your advice applied.
voxl-mini sdk version is 1.0.0
My program and spi device operates is normal.
Thanks for your advice.