What pins are available for GPIO on STM32F429I-DISCO?

MChap.1 · ‎2021-01-16

My initial thought was that while some pins are connected to other peripherals on the discovery board, that they may still be used for GPIO. Is this true, or can a pin not be used for GPIO if connected to a peripheral, even if that peripheral is not used (e.g. SDRAM, gyroscope, etc.).

TDK · ‎2021-01-16

It depends on the peripheral. Generally a pin can be used unless an external peripheral is trying to drive it, and in order to make sure the peripheral doesn't talk, you may need to hold a pin in a certain state. I think all peripherals are okay with 3.3V inputs, so shouldn't be a conflict there. The user manual generally lists the conflicts for individual pins.

If you feel a post has answered your question, please click "Accept as Solution".

View solution in original post

TDK · ‎2021-01-16

It depends on the peripheral. Generally a pin can be used unless an external peripheral is trying to drive it, and in order to make sure the peripheral doesn't talk, you may need to hold a pin in a certain state. I think all peripherals are okay with 3.3V inputs, so shouldn't be a conflict there. The user manual generally lists the conflicts for individual pins.

If you feel a post has answered your question, please click "Accept as Solution".

MChap.1 · ‎2021-01-16

That makes a lot of sense. I did see that portion of the manual, so it's mainly a matter of determining which pins are peripheral outputs and how to keep the peripheral from talking. I do need some 5V tolerant pins, but I believe there are enough pins that aren't used with peripherals that I should be fine. Thanks!