Posting here as accidentally posted under wrong topic and was deleted...
I am using an STM32F429 on a custom board. The chip is resetting once shortly after starting up, around 10 secs. I put this code at the beginning of the main function:
if (__HAL_RCC_GET_FLAG(RCC_FLAG_SFTRST)){
reset_cause = 1; // Software reset
} else if (__HAL_RCC_GET_FLAG(RCC_FLAG_PORRST)){
reset_cause = 2; // POR/PDR reset
} else if (__HAL_RCC_GET_FLAG(RCC_FLAG_PINRST)){
reset_cause = 3; // Pin reset
} else {
reset_cause = 4; // ??
}I am toggling an LED depending on the value of reset_cause. After the unexpected reset the LED for RCC_FLAG_PORRST lights up. I scoped my regulator outputs and couldn't see any change in the signal when the MCU reset, I also scoped the reset line and saw it pulled low pretty cleanly when the chip reset. This also happens when I bypass the regulators by powering the MCU directly with 3.3V from an ST-LINK.
All this leads me to believe it isn't the regulators causing the problem but some other issue with the PDR circuit or a software thing (though don't know if this sort of fault could originate from software).
My MCU connections, all solder bridges are unpopulated:
MCU power circuit:
and regulators, D5 and C38 aren't populated:
