2021-04-05 09:29 AM
I've read through the datasheet and reference manual for STM32L451REI and have been trying to nail down some definitive answers for GPIO behavior upon SHUTDOWN mode. I can't seem to find them, so I'll ask here.
In SHUTDOWN MODE:
Trying to make sure I understand behavior so I don't see erratic behavior or excess current usage.
Thanks,
2021-04-05 12:11 PM
Settings in GPIO are not used in Standby mode, the pins are either completely floating; or pullups/pulldowns can be applied by setting APC bit in PWR_CR3 and then the individual PWR_PUCRx/PWR_PDCRx bits. Read the I/O states in Standby mode subchapter in RM0394.
There are exceptions - the SWD pins can't have any of pullup/pulldown applied, and the RTC pins may be under control of RTC, see RTC chapter.
JW