I’m a n00b, but I have a requirement to make a few of my GPIO pins not output any voltage during boot.
I’ve got a new beaglebone black.
I can disable them through the /sys/class/gpio/export just fine but doing so in a bash script on boot leaves current through the pin for about 4-5 seconds before it runs my script.
So next, I looked into modifying the boot loader. I tried commenting out the bottom section of beagle.c:
/* Set GPIO states before they are made outputs
writel(GPIO23 | GPIO10 | GPIO8 | GPIO2 | GPIO1,
writel(GPIO31 | GPIO29 | GPIO28 | GPIO22 | GPIO21 |
GPIO15 | GPIO14 | GPIO13 | GPIO12, &gpio5_base->setdataout); */
/* Configure GPIOs to output
writel(~(GPIO23 | GPIO10 | GPIO8 | GPIO2 | GPIO1), &gpio6_base->oe);
writel(~(GPIO31 | GPIO29 | GPIO28 | GPIO22 | GPIO21 |
GPIO15 | GPIO14 | GPIO13 | GPIO12), &gpio5_base->oe); */
and recompiled and tested and there is still voltage coming from pin 11 during boot.
Would someone that has experience doing this at least point me in the right direction? It would be so much appreciated!