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GPIO pins for input

Posted: Thu Jan 11, 2018 7:41 pm
by jakejm79
Are there any limitations on the actual pin numbers we can use with a common ground board, obviously 5V, 3.3V and Ground cant be used (so that's physical pin 1 2 4 6 9 14 17 20 25 30 34 and 39) but I see ones labeled SDA, SDL, GPCLK, etc I assume if configured with Retrogame to use those pins those functions wouldn't be used (so as long as it's not something I need - for audio or safe shutdown) I'm free to use whichever pins I want or will I run into conflicts?

Re: GPIO pins for input

Posted: Thu Jan 11, 2018 9:03 pm
by rodocop
Skip pwm0 or pwm1 (18 and 13) if you plan to do pwm audio. Skip the spi pins too. If you don't plan to use an spi screen you can probably use those too.

https://i.imgur.com/dh9kiPi.jpg

I always just use the pins in this guide:

https://sudomod.com/forum/viewtopic.php?t=57

Re: GPIO pins for input

Posted: Fri Jan 12, 2018 10:08 am
by jakejm79
Thank you, I normally use I2S for audio, so that excludes 18, 19 and 21. I did do some searching and looks like they are all fair game unless you are actively using them for something else (audio, screen, serial connection) or power/ground. Just trying to find about 11 pins that run just about in order from physical pin 6 or so. Looks like I should just about be able to do that if I jump back and forth between the 3.3 and 5V columns as I work my way down/over.
Thanks for the help.

Re: GPIO pins for input

Posted: Fri Jan 12, 2018 10:26 am
by rodocop
Ah. I've never used I2S audio, didn't think about Those. Regardless, lots of pins to choose from!