STM32F407Z bootloader problem

[igor_s]

Posted on November 25, 2012 at 09:17

Hi,

We used STM32F103Z on one our boards, using the programming via UART1 with Flashloader Demo application. Everything was fine till the moment, when we decided to replace it with STM32F407. Of course the package is the same (144 pins TQFP), with all the reccomendations mentioned in AN2606 document were made (some stitching was made on board). And the problem arised... Some boards are OK, but some failed to programm with message ''Device not recognized''. We use the last Flashloader Demo application, downloaded from ST website (Version  2.5.0). Even more - we replaced the CPU from the board been programmed to the board that failed, and tried to program it again - it failed. But, this programmed CPU succesfully communicates via UART1 with perepherials, i.e. UART1 on board itself works fine... Unfortunately, this happened at our remote production site and I can not investigate the fail directly. Worse of all, that they sent me 2 boards that failed there, and I succesfully programmed them at my site.  Would you please to suggest at least the direction of investigation? Thank you in advance, Regards Igor  

[Tesla DeLorean]

Posted on November 25, 2012 at 14:08

Would you please to suggest at least the direction of investigation?

Consider the serial port to which you are connecting the device, and if the local setup is equivalent to the remote one. Look at the level conversion circuits and speeds being used. Look at the speed being used, and if that impacts things. The Bootloader auto-bauds using the 0x7F byte, if it gets that wrong not further communication is viable, restart the board. Determine what baud rates are unreliable vs reliable. The Flash Loader Demonstrator is hardly a production ready programming tool, you should implement your own version, ideally with enough diagnostics so you can trace the problem, and offer retry options. Pick some USB-to-Serial type converters that you can test and evaluate/qualify locally, and send those to the factory.

[igor_s]

Posted on November 26, 2012 at 09:40 Thanks for response, Clive1! It definitely concerned with USB to Seial adapter, because factory guys connected the board directly to PC's COM port - and in such configuration it works. How do you think, how adapter affects? Is it concerned with baudrate, latency or something? Have you encountered such behaviour in your experience? Thanks