Bootloader sometimes run slow.

[Tai.Cheng Chung]

Posted on May 19, 2016 at 05:12

Hi:

   My systems run STM32F427@168 MHz using external oscillator @ 8 MHz. The system will first run boot-loader then jump to main application.

 I find that sometimes the boot-time is long. After check it's due to boot-loader. So I toggle LED to measure the running speed of boot-loader.

  I found that normal speed is about 12~13 times slow speed. Since I use the normal ''system_stm32f4xx.c'' without any modification, I will support it has no bugs. Is there any hint or what can I do to check why sometimes it slow. (Note that after jump to FW, the FW will run the same system_stm32f4xx.c again, and the FW speed is 100% OK).

#stm32

[Tesla DeLorean]

Posted on May 19, 2016 at 19:21

Since I use the normal ''system_stm32f4xx.c'' without any modification, I will suppose it has no bugs.

I wouldn't, it is some very generic code that doesn't fail over well. If the HSE doesn't start within the timeout, it will drop to using the HSI running at 16 MHz. If the PLL is not started things like SDIO and USB stop functioning.

I would perhaps use a GPIO to quantify the time it is taking to start the HSE, PLL, etc.