Start USART Bootloader on STM32F070 device does not work

tj · ‎2016-05-22

Posted on May 22, 2016 at 10:50

Hi all,

i am using a Nucleo board ''NUCLEO F070RB'' and i want to start the UART Bootloader. Unfortunately the bootloader doesn�t send the Ack byte (0x79) after activation.

My procedure to start the bootloader:

- connect the boot0 pin to 3V3

- reset the board (black botton)

- send the 0x7F Byte with 9600, even parity, 1 start bit, 1 stop bit

=> at this point i expect to receive the 0x79 ACK byte from the micro

What i did till now to find what i am doing wrong:

- i checked that nBOOT1 bit in the option bytes is set to 1

- due to the fact that the F070 device has an USB interface i removed the crystal (and i opened SB50 from the NUCLEO to avoid getting clock from the debugger)

- i am quite sure that the micro is in bootloader mode, because the application doesn�t start.

- i verified my sequence with a NUCLEO-F030RB

=> here erverything works fine. The problem just excists on the F070.

=> all my HW-connections should be ok (same Pins)

I am running out of ideas :(

Any help is appreciated.

Thanks

Thomas

#nucleo-f070rb #bootloader

Tesla DeLorean · ‎2016-05-23

Posted on May 23, 2016 at 14:51

Which Pins and USART are being utilized?

Can you identify the ROM version being used?

What are the marking/production codes from the top of the device?

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Walid FTITI_O · ‎2016-05-23

Posted on May 23, 2016 at 15:40

Hi jung.thomas.001

In

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

, section'' STM32F070xB devices bootloaders'' p 44, there is a note:

''

Note: If HSI deviation exceeds 1% , the bootloader might not function correctly.

''

So It may the HSI of the device is not accurate enough, try with a HSE crystal.

-Hannibal-

tj · ‎2016-05-23

Posted on May 24, 2016 at 08:24

Hi clive1,

thanks for the replay.

I am using USART1 on PA9 and PA10. I use the same USART and the same pins in my application and there it works fine. Same connections on a NUCLEO F030 board works fine.

How can i identify the ROM Code Version? Is it part of the production code?

This evening i will send you the production code. I donÂ´t have the board with me. I tried at least two boards.

Thanks

Thomas

tj · ‎2016-05-23

Posted on May 24, 2016 at 08:33

Hi Hannibal,

thanks for the replay.

i have read the note you mentioned, therefore i tried both, with and without crystal. Nothing works. Is there any other possibility to skip the USB bootloader.

What is the indication for the bootloader to detect a connected USB interface (PA11, PA12, PA13) ?

Thanks

Thomas

tj · ‎2016-05-24

Posted on May 24, 2016 at 17:24

Hi clive1,

here is the product code:

STM32F070R8T6 GH262 98 CHN GH 447

The code is the same for all the boards i have tried.

Thanks for help

Thomas

Tesla DeLorean · ‎2016-05-24

Posted on May 24, 2016 at 18:34

The USART1 should be functional with HSI, one might try different baud rates. Connecting it via a VCP might be problematic, the bootloader will be sensitive to glitches as the 0x7F is a pattern that is being measured, rather than received. You could use a scope to see if there is an 0x79 response at some other baud rate.

Absent USART/USB connectivity to the loader to query its version, one would have to download via SWD and manually dig it out. The ROM is 12KB located at 0x1FFFC800..0x1FFFF7FF[0x3000]

Not a part I'm using, but the codes should let someone at ST identify if there is a parts/batch issue.

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tj · ‎2016-05-24

Posted on May 24, 2016 at 19:29

Hi clive1,

the USART is connected to a FTDI Evalboard ''UM232R'' which is mounted nearby the NUCLEO board. I already checked the RX and TX line with my scope. I see a perfect 0x7F on the RX line bt nothing (constant high) on the TX line. I also checked different baud rates (9600, 115200).

I checked the bootloader Version. (Adress 0x1ffff6a6 Version: 0xA2). This is what i expect. AN2606 tells me that it should be USART bootloader Version 3.1. Do you Need more numbers from the bootloadercode?

We could also debug the bootloader. I could set breakpoints and see if we hit them.

Thanks for help

Thomas

tj · ‎2016-05-30

Posted on May 30, 2016 at 12:41

Hi all,

somebody else who has an idea??

Thanks

Thomas

Julien SOTIERE · ‎2017-06-13

Posted on June 13, 2017 at 11:43

Hi Thomas

Do you find the problem ? I am the same problem, the boot0 is hight but the stm32f070cb doesnt respond in bootmode.

Thanks.

Julien