2023-11-29 07:36 AM
I tried 3 boards F407vet6 x2 and F427 x1.
I found both pullup and pulldown gpio output in PP and OD will put a low voltage. 20mV in down and 50 mv in up.
This situation is based on the stdperiph-Lib
However, use the Hal-Lib to implement the gpio output, it will work well.
I've tried to search for simillar issues on internet, but none.
2023-11-29 07:49 AM
Read out and check/post the GPIO registers content during your test.
JW
2023-11-29 08:17 AM
The SPL can't change the low-level hardware behavior. It's accessing the same registers as HAL and the registers dictate the behavior of the chip.
Likely to be some other explanation.