Emulating Raspberry Pi GPIO on Linux Mint PC
lazarus / 32-Linux

----------------------------------------------------------------------
BosseB · 2016-02-29 07:58

I am working on a data acquisition controller targeting Raspberry Pi2
hardware.
I have installed FPC/Lazarus on a Pi2 unit so I can program and
build/debug there, but the platform is rather limited in performance
so I have followed advice to move to a Linux based development system
instead.
So now I have duplicated the installation on a Linux Mint 17.3 MATE
virtual computer on my Win7X64 laptop using VMWare Workstation 12PRO.

What I would like to discuss is how I could handle the hardware
differences between a Pi2 (ARM7) and a virtual PC environment.
Specifically I need to use the GPIO on the RPi2 in order to switch
on/off power and similar things on the actual target hardware.
So I have tested this on the RPi2 platform and the GPIO manipulations
work just fine from Lazarus using the PiGpio unit (after I patched it
for the register address differences between the original RPI and the
RPi2).

Now I would like to have some way to make FPC/Lazarus use the GPIO on
the physical system if running on a Pi2 hardware but otherwise
redirect to some kind of GPIO emulator if not on an RPi2.

Has this been done before and if so how was it accomplished?
For development/test/debug I will not need physical signals, but I
need to make sure that the code will compile on an RPi2 platform so it
will actually use the GPIO.
During development it is sufficient if I can see the states of the
GPIO outputs and toggle the inputs, possibly in some simulation window
or such.

----------------------------------------------------------------------
Thaddy · 2016-02-29 09:38

It should not be very difficult to write a Daemon that simulates the
GPIO, but rather than ask here ask on  the Raspberry Pi forum if
something like that is already available (in any language).
I would be interested in writing one, but I am notoriously lazy in
doing it from scratch.

----------------------------------------------------------------------
BosseB · 2016-02-29 10:07

I did post a question there but probably in a too obscure place...
(Programming/Other)
Somehow it seems like the GPIO simulator/emulator is only needed if
one programs on a different platform than the RPi and therefore the
RPi forums might not be such a good place. They seem not to know much
about Pascal there for example.
OTOH in other forums they probably know nothing about the Raspberry Pi
instead....

----------------------------------------------------------------------
Thaddy · 2016-02-29 10:16

It should be in "Bare metal".

----------------------------------------------------------------------
BosseB · 2016-02-29 10:38

Thanks, I asked the admins to move  the thread.