[Vm-dev] Re: Interfacing with the i/o pins on the Raspberry Pi et al

On 04.08.2015, at 20:14, Eliot Miranda eliot.miranda@gmail.com wrote:

Hi All,

I'm curious about interfacing Squeak with the i/o pins on the Raspberry Pi et al.  Should we write a plugin?  Does the FFI work just fine?  What's a good guide?  Who's done this already?  What was good/bad about the approach you (if it is you) took?

I’d think the sysfs should be usable without any additional VM support? I guess that what Dimitris means with “sockets”:

http://elinux.org/RPi_GPIO_Code_Samples#sysfs http://elinux.org/RPi_GPIO_Code_Samples#sysfs

Otherwise I’d go for a lightweight plugin solution using direct IO:

http://elinux.org/RPi_GPIO_Code_Samples#Direct_register_access http://elinux.org/RPi_GPIO_Code_Samples#Direct_register_access

Advantage (besides being most efficient) is that there are no dependencies at all, and it does look pretty trivial.

If we desire an interface similar to the WiringPi lib (which is GPL) then that should be easily accomplished in the image.

- Bert -