STM32F070CBT6 UART Bootloader does not work

[usrfaqr]

Posted on June 13, 2016 at 20:32

Hi, I have evidence that the UART embedded bootloader of the STM32F070CBT6 does not work. Is this expected ? I have tried the boot sequence with other STM32 variants for years, and I cannot find any written explanation on why the embedded UART bootloader simply does not work for this particular uC type. Is STM32 aware of this ?

[Tesla DeLorean]

Posted on June 13, 2016 at 20:53

You'll need to pull the manufacturing/productions codes marked on the top of the device to better isolate the specific part/batch you are having issues with.

Can you access the device via the SWD port, and in other mode is it functioning normally?What is the BOOTn setting in the Option Bytes?The System Loader will be sensitive to transitions on any other pins/interfaces it might expect to see communications on. Refer to the documented list of pins for the device.

[Walid FTITI_O]

Posted on June 14, 2016 at 16:29

Hiquintero.francisco,

First, I recommend you to take a look to the

http://www.st.com/content/ccc/resource/technical/document/application_note/b9/9b/16/3a/12/1e/40/0c/CD001675pdf/files/CD001675pdf/jcr:content/translations/en.CD001675pdf

, p 43 to see th recommendation about bootloader use within you device. AS mentionned, if the HSI is used and its clock not enough accurate,the bootloader might not function correctly. So, try use the HSE as clock source, or see about HSI calibration as done in this

https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/stm32f0%20effect%20of%20bootloader%20on%20usart&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&currentvi...

. Come back to tell if this solve your problem. -Hannibal-