STM32F3 Discovery Bootloader No NACK Received

[Fong WH]

Posted on November 02, 2017 at 14:36

Hi,

I'm facing a problem of getting the STM32F3 Discovery board bootloader to work. AN2606 calls for pattern 2 to be applied so I pulled up the BOOT0 pin. A check with STLink shows the nBOOT1 bit is 1 so upon powering up the board, the application firmware inside the MCU did not run. But when I send 0x7f through USART1, there is no response from the bootloader.

Anybody has any idea what I'm missing?

[Tesla DeLorean]

Posted on November 02, 2017 at 16:14

USART needs to connect to at CMOS serial levels, need to be using Even parity, ie 9600 8E1

The 0x7F is a single character, need to use something like RealTerm in Hex mode.

Really no idea from question how you've actually got this wired up or how data is applied and reviewed.

[Fong WH]

Posted on November 03, 2017 at 09:06

Hi,

Thanks for your reply. When you mentioned about wiring, I did another check and found out I had soldered the USART1 Tx to an adjacent pin instead of PA9. Correcting it returns an NACK now

For info, I'm using a FTDI USB to Uart bridge to interface with the 

STM32F3 Discovery board. The Tx output of the Uart bridge is buffered and pulled up to the 3V source on the Discovery board. I then used a Windows Terminal App to do the communications.