Hi! I m using the uC STM32G431 to drive a H-bridge. I saw that the reset value of GPIOx_PUPDR for PWM pins is 0 which means they are in state "no pull-up, pull-down", so they are floating. I m afraid that they could activate the driver of MOS. What to do?

OIoni.1 · ‎2021-03-27

JPeac.1 · ‎2021-03-27

You need to ensure the H-bridge is always turned off when the ST ports are in analog mode, from reset to end of timer configuration. If you have a specialized bridge driver check to see if the enable inputs have built in pull down resistors. If not, or you are using discrete drivers, you need to add an external pull down to hold off all bridge gates. If not you will likely experience shoot thru current at reset time, eventually damaging the bridge. Do not rely on the internal PU/PD in the ST GPIO port.

Jack Peacock

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JPeac.1 · ‎2021-03-27

You need to ensure the H-bridge is always turned off when the ST ports are in analog mode, from reset to end of timer configuration. If you have a specialized bridge driver check to see if the enable inputs have built in pull down resistors. If not, or you are using discrete drivers, you need to add an external pull down to hold off all bridge gates. If not you will likely experience shoot thru current at reset time, eventually damaging the bridge. Do not rely on the internal PU/PD in the ST GPIO port.

Jack Peacock

OIoni.1 · ‎2021-03-28

Thank you!