how to force a fix ''LO''(=Vss) in a GPIO pin of stm32f4?

[shlomo]

Posted on August 09, 2015 at 13:04

how to force a fix 'LO'(=Vss) in a GPIO pin of stm32f4?

[raptorhal2]

Posted on August 09, 2015 at 16:21

Pull down resistor ? GPIO reset code?

Cheers, Hal

[Tesla DeLorean]

Posted on August 09, 2015 at 17:53

Your question is very awkwardly framed.

You'd get a LOW state (VOL) by configuring the GPIO pin in a PP or OD mode, and writing a zero bit to the GPIOx->ODR controlling the specific pin.

[jj2]

Posted on August 11, 2015 at 12:47

Awkwardly framed ++;  (effort-lite posts skimp upon clarity, needed detail)

Why does a ''fixed'' logic low require a GPIO pin?   Hard wire to ground should well satisfy. One suspects you used ''fixed'' improperly - and meant logic low upon ''start-up'' - which will be violated by the MCU (briefly) until the code forcing the GPIO to output has executed...