In what document can I find a table as to what peripherals are directed to which I/O pins? Am am currently working on the STM32446RE but have not found it for other chips either.

[KiptonM]

For instance What pins can UART1_TX come out on?

Or what peripherals are attached to PA5?

I would think there was a table somewhere.

I have looked in the RM0390 Reference manual but they say Alternate Function 0 - 15 but do not say what the alternate function is.

STM32F446xC/E Document does not have it either.

PM0214 Programming manual is too generic.

I would have thought it was here somewhere but I cannot find it.

https://www.st.com/en/microcontrollers-microprocessors/stm32f446re.html#

[Pavel A.]

The CubeMX or CubeIDE will conveniently show you exactly this.

Select UART1 and it will assign pins for it and show alternatives.

-- pa

[KiptonM]

It seems to choose for me, but does not let me see the options. I have to take what it chooses. At least I have not found how to change it so far.

Are you saying it is not documented anywhere?

[KiptonM]

I am looking at the USART3_TX and the MX said it is PB10. I do not see any option to change it. Right -mouse click, left mouse click does nothing. Either mouse click with the Shift, Ctrl, or Alt does nothing. There is no context help.

I do not know what you are talking about.

[Tesla DeLorean · Accepted solution]

It is all documented in the Data Sheet, on the page you cited. See Table 11, it shows the pins, and the 16-way mux options for each.

https://www.st.com/resource/en/datasheet/stm32f446re.pdf

[KiptonM]

I do not know how I missed it but that is exactly what I was looking for.

Thank you.

[Pavel A.]

To show alternative location of a pin, find it on the pinout view (the nice green picture of the chip with all the pins).

For example type in the search box USART1_RX and it will show the pin assigned to USART1_RX.

Then hold CTRL and click on that pin. While you're holding the mouse button, alternative pins for the same function will be highlighted.

Not every function has alternatives. If the selected pin does not have alternatives, Cube won't highlight anything else.

Now you know =)

-- pa