Greetings, I have been evaluating the Rock 4C+ as a replacement for a Raspberry Pi and I have been unable to control certain GPIO lines. Let me explain the environment.
Using the Radxa supplied Debian release from 230315 I put it onto a SD card and booted it up with the only frustration being SSH was not set to automatically start on boot; easily fixed with.
sudo systemctl enable --now ssh
Ran apt-get for the libgpiod-dev and a few other packages I would eventually need.
sudo apt-get -y install git libgpiod-dev libsdl2-dev libsdl2-image-dev libsdl2-mixer-dev libsdl2-ttf-dev libavcodec-dev libavformat-dev libswscale-dev zip unzip libpugixml-dev liblog4cxx-dev liblog4cxx11 cmake build-essential stress-ng i2c-tools libtool
I adapted a c++ test framework I had for the RPI that would use libgpiod to claim specific lines as an output and toggle them every 25ms for awhile. Thus giving me enough time to probe with a scope and ensure all is working. Additional testing was done using the gpioset CLI
I found that I could control pins : 7, 11, 13, 16, 18, 22, 29, 31, 32, 33, 37
I was disappointed that I could not control pins : 19, 21, 24, 26
I understand that 26 on the Rock 4C+ is an ADC and so will need to handle it differently. But I am not sure where to begin to resolving why I cannot control 19, 21, 24. Is this because SPI1 is enabled? If so how do I disable it? If this was SPI1 I would have thought I would see something on Pin 23 as that is listed as the SPI1_CLK
I’ve used the rsetup utility and don’t see an overlay enabled related to SPI1 ; I do intend to enable UART2 and I2C7 but that is a later stage.
Any help in getting the system to a configuration state to allow me to control pins 19, 21, 24 would be appreciated.