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STM32F407VGXT DIscovery GPIO state at start_up

Question asked by Bruno Brentegani on Apr 20, 2018
Latest reply on Apr 20, 2018 by Bruno Brentegani

Hi all,

I'm using stm32f4 discovery with HAL drivers to realize a Synchronous BOOST DCDC.

When the system is turn on, the gpio PE8 and PE9 configured as PWM pins of TIM1,(in particular PWMOUT_CH1 & PWMOUT_CH1N) goes in SET state and for a  few milliseconds keep the mos of the converter in ON state causing a little initial short circuit.

At startup PE8 and PE9 are in high impedance state?

If so,can i avoid this issue with a 100k pull down resistors?

There are software solutions to this problem?

Best regards