Affordable and flexible platform to ease prototyping using a STM32F401RET6 microcontroller.

F401RE out of reset time vs F103

15 Nov 2015

Hi - I was wondering if someone else can verify what I am seeing on my F401. I noticed that coming out of reset into main is taking over 5 seconds. On my F103 it comes up almost immediately as expected. Both boards are just running Blinky code.

Since I can't debug the bsp/cstartup from the web I have to guess that there must be something in the bsp that is hanging on init.

I'd appreciate some feedback if on this if you have both boards to validate what I'm seeing.


15 Nov 2015

See this:

TL;DR, it is a combination of idiotic long timeouts in the F401 code and the clock source your board is using. It should with correct connectors use a clock source which allows it to start immediatly.

15 Nov 2015

Yep. My suspicion was that there was a 5 second timeout in the code in the startup somewhere. Found it It's defined as "HSE_STARTUP_TIMEOUT" in stm32f4xx_hal_conf.h And also, my version of F401 is "C-01" which is not shipped with the HSE clock jumpered in. Just saw that in the Nucleo manual.

So it was hanging in the HSE wait-for-ready code for the 5 seconds then switching to HSI. I plan to jumper my version over to HSE and it should be good. For now I changed that awful timeout to 500msec and it's acceptable.