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STM32 flash download demo issues with connecting

Associate II
Posted on May 09, 2013 at 16:53

Attached are two logic analyzer traces.  You can download the software to view them from here:

What you see is that when I use the flash loader demonstrator tool, the connection fails.  It fails for the following reason.  The bootloader is not correctly determining the baud-rate.  The bootloader is sending 0x7F at 115200 bps, but the bootloader configures itself as approximately 11000 bps.

When I use my own flash loader you can see that the bootloader correctly configures itself as 115200bps.

The particular processor I am targetting is the STM32F205ZC

From what I can tell the only difference is that for the ST-tool the TX line goes high only 600us before the 0x7f is sent.  In my case the TX line goes high long before the 0x7f is sent.

Is there a fix for this from ST?

I am using version 2.6.0 of the flash loader demonstrator from Nov 2012.

Note: in my traces the boot0 and reset lines are inverted polarity from the data sheet.

Posted on May 09, 2013 at 19:11

Is there a fix for this from ST?

It's in ROM, it is what it is.

It tests for the auto-baud data pattern once after reset.

Make sure you're using 8-bit Even parity. For an STM32 this would require 9-bit mode.

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Associate II
Posted on May 09, 2013 at 19:38

Here are pictures if that helps.

I realize the bootloader is in ROM, but it is the same bootloader in both cases. The only difference that I can surmise that accounts for the different behavior is the way the host drives the TX line.


Attachments :

Flash_Downloader_Tool_Failure_to_Connect.jpg :

Personal_Downloader_Tool_Success_to_Connect.jpg :