PC2_C PC3_C on STM32H743VI

[EthanMankins]

I am using STM32H743VI LQFP 100 pin. There is no PC2 and no PC3 so I need to use PC2_C and PC3_C as SPI MISO and MOSI respectively. I heave read many forums on here claiming there was a bug in the silicon making PC3_C not suitable for SPI communication. I am wondering if this is still true or if I will be able to properly use PC2_C and PC3_C as SPI pins.
To my understanding while reading the reference manual and data sheet there should not be a problem and the switches between pads is closed by default. This leads me to believe that I can use PCx_C as PCx SPI without any extra modification. Please let me know if this is true.

Thank you,
Ethan Mankins

[FBL]

Hi @EthanMankins 

For limitations on Px_C IO, you can find the output current sunk by Px_C 1mA.

There is an errata before where some datasheets may not state that the current sunk or sourced by Pxy_C pins is limited to 1 mA when the analog switch between Pxy and Pxy_C pads is closed. 

For now, AFAIK, these updates are well documented. 

[SofLit]

Hello @EthanMankins ,

The constraint on PXY_C pins is the current as the internal switch doesn't support more than 1mA:

DS12110 Rev 10:

From the errata ES0392 - Rev 13:

Errata on the max current and the ETH function:

So you need to insure that you have =< 1mA load on the pin.

How the switches are configured by default? Please read this article: https://community.st.com/t5/stm32-mcus/faq-default-state-of-stm32h7-switches-connecting-pxy-c-and-pxy/ta-p/49300

Hope I answered your question.

[MHoll.2 · Accepted solution]

SPI on Px_C works, but the max. frequency is limited by the max. output current (1mA) and the load capacity.

So if your SPI is not required to be very fast You should be ok.