Read 'fn' key or use wiringPi

Using: ubuntu server 22.04 Khadas 5.4.125 #1.0.10

Hi there,

How do I use the ‘fn’ key within linux?

Per schematic it is connected to A311D2 per ADC_CH2 (why a digital I/O is connected to an ADC I do not quite understand, but ok). DOCS mention wiringPI for ADC_CH3 and CH_6 (PinHeader) so I assume CH2 can be read there as well.

However wiringPi does not seem to be installed and installing via apt is installing an incompatible version

“Oops: Unable to determine board revision from /proc/device-tree/system/linux,revision
or from /proc/cpuinfo
→ No “Revision” line
→ You’d best google the error to find out why.”

Any ideas?

You might have to wait until they finish testing an “official release”. Device tree stuff is rather complicated and takes a long time to test and get working properly.
What I found that is much simpler is get an A/D that connects directly to the USB port. It will send text strings to the com. port upon insertion. Just read UART and parse the data. Very easy and simple to read UART.

So the key is bound. (I’ve scanned through the device tree and found it was mapped to keycode 102 KEY_HOME)

showkey is showing a keypress and release event.

No I do just need to figure out how to check for it in a bash script. (Documentation would be great though)

@foxsquirrel I am just testing my scripts for gps receiver tests and need a trigger for log and stop log (without display or keyboard attached). a custom add on with a uC and additional gpio capabilities (as well as can-fd, gps, lora) will follow.