Good news.  The issue appears to be resolved by using a bit shift as in:

gpio = 1 << 15;    // to toggle P8.11
or
gpio = 1 << 14;    // to toggle P8.12

Mike

On Fri, Apr 28, 2017 at 11:34 AM, M Pitman <[email protected]> wrote:

> This is a followup to a past post on the PRU's.  I'm looking to provide a
> clock pulse in the 100kHz range plus send additional pulses out of the PRU
> and receive a couple other pulses back from a sensor.
>
>
>
> I've been able to load the device tree overlays for pins P8.11, P8.12,
> P8.15, P8.16 and P9.24 with no problems.  For output, the overlay sets the
> mode for pins P8.11 and P8.12 to 0x06.  Plus, I've been able to generate
> the clock pulse on P8.11 and the other needed outgoing pulse on P8.12 using
> assembly language but I get the general impression that going forward the
> preferred method for programming the PRU's is with C.  So for testing I've
> tried to get PRU_gpioToggle.c to work but for some reason I can't get pins
> P8.11 or P8.12 to toggle.  Instead, they just read a constant 0 volts.  In
> the code, gpio is set to 0x000F thinking this should be pin 15, as in
> pr1_pru0_pru_r30_15. Not being certain for the format of this number I've
> also tried 0x1111 but with the same results.
>
>
>
> PRU_gpioToggle compiles OK and the .out file is copied to
> /lib/firmware/am335x-pru0-fw  The PRU's are stopped and restarted with
> rmmod -f pru_rproc and modprobe pru_rproc.  dmesg shows they stop and start
> as expected.  However, still no luck with the toggling.
>
>
>
> uname -a reads 4.4.54-ti-r93 #1 SMP.
>
>
>
> Does anybody have any idea what I’m doing wrong?
>
>
>
> Thanks
>
>
>
> Mike Pitman
>

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