STM32F373 DFU bootloader won't start

[Mason Malvinni]

Posted on May 10, 2018 at 22:27

I have a STM32F373 design running with 16MHz HSE. My application works fine, but I am having trouble running the DFU bootloader. The host computer never sees a USB device. I have a previous F405 design using the same crystal that works without issue. 

If I increment a variable in the loop that waits for the HSE to start I see that my F405 design takes between 170 and 200 cycles to start. The same test on the F373 counts to around 120 consistently.

This leads me to believe the crystal is starting quick enough. 

I read the bootloader ID in memory using STLINK-utility which reads 0x41. This is the same as the documentation which states that it should be DFU and USART compatible.

I have verified the state of BOOT0.

The only thing I can think to try at this point is verifying that the actual DFU code is present in the system rom. I'm not sure how to do this yet, but this is the only lead I have left.

Can anyone please give me some insight or pointers on other possible causes of my issue? This exact setup is working perfectly on all of my F405 designs.

[Tesla DeLorean · Accepted solution]

Posted on May 10, 2018 at 23:43

Pulling the ROM would allow you to double check version

From the notes for the F373 USB boot mode, make sure you have a 1.5K pull-up on USB_DP (PA12)

http://www.st.com/content/ccc/resource/technical/document/application_note/b9/9b/16/3a/12/1e/40/0c/CD00167594.pdf/files/CD00167594.pdf/jcr:content/translations/en.CD00167594.pdf

 

[Mason Malvinni]

Posted on May 11, 2018 at 01:54

The 1.5K pull-up was the issue. It's not necessary on the F405 which explains my observation. Thank you so much Clive. I will definitely take note of this in the future.