STM32L433 PH3/BOOT0 doesn't work as input

[ArminT]

Hi all,

I am using an stm32l433rct6 (tqfp64 package) in a project and am trying to reconfigure the boot0/PH3 pin for input, but this doesn't seem to work. I can configure the pin as output, which works fine. But when configuring for input, the pin always reads 0, and the interrupt isn't triggered when the voltage on the pin changes. Tried it on a Nucleo-l433RC-P with the same result. Is this a known issue? It is not documented in the datasheet/manual/errata sheet. Has anyone else encountered this?

[waclawek.jan]

> But when configuring for input, the pin always reads 0

At that moment, read out and check the content of GPIOH registers.

JW

[ArminT]

Before config, GPIOH->MODER=0xCF which means PH3 is in analog mode (and PH0 and PH1 are in analog mode). After config, MODER = 0xF so PH3 is in now input mode. All other registers are 0. At the moment of read-out MODER is still at 0xF, but IDR stays 0 no matter what I do with the voltage on the pin. I only see this behavior on PH3, not on any other GPIO line.