Single board computer GPIO HAL?

Pretty sure it's not quite discontinued yet, Ameridroid is still taking preorders. Even so the CPU isn't really their problem, its the 2.5gb nics. The J4125 on the Odyssey is likely pin compatible with the H2+'s J4115 because they both started out with a J4105. These are just minor refreshes of the CPUs, they bump up the clock speed and continue selling it. Seeed's boards have a bunch of different serials because of soldered RAM and EMMC options some are still in stock and Seeed told me they will be restocked on the 21st.

So if the H2 doesn't pop back up they either just don't want to run it anymore or they don't want to make the changes for peripheral chips that they may need to substitute.

I just found the gpio docs in the linux kernel.
www.kernel.org/doc/html/latest/driver-api/gpio/index.html

I think with the gpio numbers and these docs, you probably have enough info to write a gpio kernel driver. Beyond me though..

I saw that too. I think a LinuxCNC hal driver needs to access the registers directly, going through the Kernel driver might not be fast enough. Maybe someone can chime in.

I have no idea what the hell I'm doing tho. Once I get enough info I'll figure out who I can bribe to hook me up with a LinuxCNC driver.

Before now I hadn't powered up the board, I was mostly going by what I've seen on the Seeed forum and such. I got Manjaro installed, apparently the /sys/class/gpio thing is the old Linux way of accessing GPIO so it doesn't just work in Arch based distros. I installed libgpiod and it's dependencies. There are tools to detect the GPIO but it just shows some obscure info relating to 4 "gpiochip"s. I came across this thread on the Seeed forum where someone Traced out all of the GPIO physical pins and mapped them out.
forum.seeedstudio.com/t/gpio-pins-not-re...ing-in-code/252187/3

I have no idea if libgpiod respects RT-preempt or how any of that works

here is another manufacturer for SBC boards

www.impulse-embedded.co.uk/systems/singl...rd-computer-kits.htm

they do quite a few options if you browse the site, the costs of what I was looking at 12-18m ago was not too bad.

it's just another option.....

blazini36 wrote:

Before now I hadn't powered up the board, I was mostly going by what I've seen on the Seeed forum and such. I got Manjaro installed, apparently the /sys/class/gpio thing is the old Linux way of accessing GPIO so it doesn't just work in Arch based distros. I installed libgpiod and it's dependencies. There are tools to detect the GPIO but it just shows some obscure info relating to 4 "gpiochip"s. I came across this thread on the Seeed forum where someone Traced out all of the GPIO physical pins and mapped them out.
forum.seeedstudio.com/t/gpio-pins-not-re...ing-in-code/252187/3

I have no idea if libgpiod respects RT-preempt or how any of that works

The last time I played with ports at the hardware level it was in DOS before Linuxcnc and Mach1 existed.
My understanding is that hardware ports were mapped to a memory address so if you wrote data to that address, it was transmitted to the hardware.

But this is low level stuff so the kernel has to be involved.

Given the kernel includes some procedures and even header files to support GPIO ports, I would use them. Heck, its in the kernel so if you patch the kernel to support  PREEMPT_RT, surely it will work!