STM32f4 internal pull down, external pull up

thommagn · ‎2014-06-25

Posted on June 25, 2014 at 11:55

Hi,

I'm using an STM32F4 and have configured IOs as pwm outputs with internal pull down. These pins have been connected to an input of another chip which has a 5V pull up on its inputs.

After some time the processor broke down. May this be the issue? I'm not quite sure I understand why, but I highly suspect this since its the only thing that was connected.

John F. · ‎2014-06-26

Posted on June 26, 2014 at 09:19

Probably 5V got somewhere it shouldn't. Did the microcontroller get hot? The pull-up pull-down currents are normally well below the ''latch-up'' currents which cause chip failure. Your circuit probably does not handle the interface properly. Get a hardware designer to look at it or post it here.