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CGalv
CGalv
Associate III
January 12, 2020
Solved

STM32F745 suddenly is extremely slow - have I bricked it?

  • January 12, 2020
  • 3 replies
  • 842 views

Hi,

I've been working on programming my STM32F745 for some months now, step by step playing with the different peripherals. So far so good. I've been also doing step-by-step debugging with OpenOcd and STLink V2.

Today things started to look a bit weird and I decided to revert my code to an old commit that just blinks 2 LEDs (I know it has been working before).

To my surprise, the behavior of the chip is now veeery slow and erratic. Instead of blinking my LEDs every 100 ms, it does every 3 seconds. It's not even consistent, sometimes it blinks faster than others (doing any change or touching the chip).

What happened?! The code was working before and I flashed it as usual. Did I brick the chip? What can cause the processor to go so slow?

This topic has been closed for replies.
Best answer by CGalv

It seemed to be a hardware issue! I unsoldered the SWD cables and clean the board with alcohol and powering up via USB it started to work fine as usual! Probably the SWD soldering got old and was producing some interference. I'll see if I can do the connection in a more robust way.

Thanks for the help!

3 replies

Tesla DeLorean
Tesla DeLorean
Guru
January 13, 2020

>>What can cause the processor to go so slow?

Usually one of the clocks doesn't start, or the PLL doesn't lock, and it ends up running from a slower 64 MHz HSI source

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waclawek.jan
waclawek.jan
Super User
January 13, 2020

> Today things started to look a bit weird and I decided to revert my code to an old commit that just blinks 2 LEDs (I know it has been working before).

Is this a simple loop-delay-based blinking? Does the behaviour change when you disconnect the debugger? Is there any external hardware connected? Check power supply. Observe the reset pin using oscilloscope.

JW

CGalv
CGalvAuthorBest answer
Associate III
January 13, 2020

It seemed to be a hardware issue! I unsoldered the SWD cables and clean the board with alcohol and powering up via USB it started to work fine as usual! Probably the SWD soldering got old and was producing some interference. I'll see if I can do the connection in a more robust way.

Thanks for the help!

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