About alternate function of STM32F746

[勝後藤.1]

Hello,

STM32F74xxx Reference manual (RM0385) 6.3.2 I / O pin alternate function multiplexer and mapping has the following description.

After reset the multiplexer selection is alternate function 0 (AF0).

I think that when AF0 is selected, it will be assigned to the following functions.

After resetting these pins, will the clock be output until the initial setting of the register is completed?

PA8 is assigned to MCO1.

PC9 is assigned to MCO2.

Goto

[Bob S]

I don't know specifically about the F7xx, but look at the GPIO MODER register. Most STM32 CPUs have the mode settings default to "analog mode" (except for JTAG pins). So while those pins will have the AF selected as you noted, that AF won't be active until you change the MODER bits to "10" (binary) for "alternate function".