Hello again, I'm really getting stuck with not being able to find out basic stuff. Sorry if I've missed something obvious but I've been trying to do something simple all day and still getting nowhere.
I want to be able to communicate between the fpga and the bbb so I thought an easy way to get started would be to use the shared pins. For example fpga pin 105 is connected to bbb p8.13.
My fpga program just connects a button (also couldn't find this documented anywhere) to the led and pin 105. I can see the pin changing with my multimeter.
Previously on a bbb, I'd export the gpio with :
root@arm:~# echo 23 > /sys/class/gpio/export
then be able to inspect the value. Which doesn't work. Neither does the Adafruit python library.
So maybe the overlay isn't setup to handle these pins. I can't find in any of the source where the overlay is defined. I've searched /lib/firmware for the overlay (which seems to be loaded when I look at the slots:
0: 54:P---L BB-BONE-LOGIBONE,00R1,VALENTFX,BB-BONE-LOGIBONE
There is an "old" dts file in the repo ./old/beaglebone_old/logibone.dts but that file isn't in /lib/firmware.
So where is the overlay defined?
How can I access the GPIOs from userspace on the beaglebone?
Am I missing a whole trove of documentation somewhere?
Sorry for all the questions,