F4 discovery doesn't start properly if I use USB to serial adapter connected to Serial 4 (A0,A1)

Posted on Wed 3rd, December 2014

• #1

Andrey

Hi, all!
Seems to It because of BTN1. If It pressed, it doesn't start also. How can I disable this feature? To start in case - if A0 pin pulled up, or not.
Thanks!
• #2

Gordon

Yes, it is so that you can't 'brick' your device by writing dodgy code that runs at startup. I'm afraid there is no way to disable it - you'd have to compile your own version.
• #3

Andrey

Gordon, could you please tell how to move those BTN1 functionality to another pin.. To A6 for example. I checked system_stm32f4xx.c from \targetlibs\stm32f4\lib but didn't get any idea how to manage It...
• #4

Gordon

Just edit boards/STM32F4DISCOVERY.py and change the pin name for BTN1.

Remember there will still be a pullup(or down) resistor on the F4 board though, which you may want to remove.
• #5

Andrey

Thanks! It was pretty easy :-).

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