On Thu, 18 Jun 2020 09:11:39 -0700, in gmane.comp.hardware.beagleboard.user
P B <mmmbarley-re5jqeeqqe8avxtiumw...@public.gmane.org> wrote:

>
>I've used config-pin in the ways you've described from the IDE, but have
>not incorporated it into C++ program. Will look for examples
>

        Well, there is always the old C-lib system() call
https://www.tutorialspoint.com/c_standard_library/c_function_system.htm

        Or managing to read the config-pin /script/ source and figuring out how
to invoke the equivalent directly <G>

>I want to ensure the pump is not triggered from any noise.  Perhaps I
>misunderstood this feature.
>

        If you need to prevent the pump for doing anything during system
start-up, you likely need to put the pull-up/-down resistors on the pump
inputs themselves, where they won't be affected by changes in the pin-mux
settings. However, take into consideration that recommendations are that
/no/ voltages be applied to I/O pins before the board itself is powered --
which implies having some sort switched buffer between the I/O pin and the
pump control with its pull-up/-down if it uses an external power-supply
rather than one controlled by the Beagle itself.



        The heavily promoted libpruio bothers me for some reason -- among them
being that it requires one of the two PRUs to be dedicated to it, so not of
use if one has an application that needs both PRUs; and that control chain
-- Linux app sending command to PRU application to modify pin-mux so Linux
app can make use of new state [Does this mean the kernel may have a
disconnect in what /it/ thought the pin-mux state was, or does the PRU
somehow update the kernel]. OTOH -- if the author could get it to work on a
BB AI (which has two /pairs/ of PRUs, and currently has nothing for
run-time pin-muxing -- requiring device tree edits for any thing that is
not a default)...



-- 
Dennis L Bieber

-- 
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