When using a GPIO pin as output, is the offered voltage stable? Imagine I want to use it to enable (or disable) an LDO, is it okay to connect the GPIO output to the enable pin directly?

AZube.2 · ‎2022-04-28

MasterT · ‎2022-04-28

Check data sheet for your LDO, if Logic High within 3.3V.

I wouldn't connect uCPU directly with enable pin, better to set a resistor in series, to stay safe in case of whatever may happened to LDO - power domain is always most vulnerable part of the circuits. 10k - 100k

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gbm · ‎2022-04-28

If the logic level was "unstable", the output would be useless.

My STM32 stuff on github - compact USB device stack and more: https://github.com/gbm-ii/gbmUSBdevice

TDK · ‎2022-04-28

Yes, the output will stay high if you set it high, and low if you set it low, until you change it, or the chip loses power or resets.

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AZube.2 · ‎2022-04-28

Perfect thanks!

MasterT · ‎2022-04-28

Check data sheet for your LDO, if Logic High within 3.3V.

I wouldn't connect uCPU directly with enable pin, better to set a resistor in series, to stay safe in case of whatever may happened to LDO - power domain is always most vulnerable part of the circuits. 10k - 100k

AZube.2 · ‎2022-04-29

Sounds reasonable now that you said it! Thanks for the tip:)