stm32w IAP BOOTLOADER protocol

[petr2399]

Posted on July 06, 2011 at 20:03

Hi,

Please, witch protocol uses stm32w device if nBOOT is selected (and serial-link-bootloader is selected) ? Is it USART protocol used in the STM32� bootloader (AN3155) ? Because, my stm32w device in bootloader mode responds to any character, also 0x7F - start sequence with NACK (0x1F).

Thank you for answer.

#lmgtfy #stm32w-bootloader-nboot-nbootmode-protocol

[Tesla DeLorean]

Posted on July 06, 2011 at 21:09

Perhaps AN3262 - Using the over-the-air bootloader with STM32W108 devices

http://www.st.com/stonline/products/literature/an/17845.pdf

http://www.st.com/stonline/products/literature/an/17845.pdf

IAP suggests an application based protocol, not the bootloader, ST has typically used YMODEM or DFU

Pretty much a first page hit with Google ''stm32w BOOT LOADER''

[petr2399]

Posted on July 06, 2011 at 23:14

Yes, sorry, thank you for immediate answer.

I thought in-circuit programming (ICP) to the separate stm32w chip. In programming manual (PM0073 STM32Wxxx Flash memory microcontrollers) are the ICP options identified JTAG, SWD protocol or the boot loader. My interest is this boot loader, no JTAG and SWD interface.

I ask

 

because

 

I

 

take up

 

other ways of

 

programming

 clear 

stm32w

 

except

 

JTAG

 

and

 

SWD, if it is possible (but ICP, no application programming).

Thanks.

[Tesla DeLorean]

Posted on July 07, 2011 at 01:09

I'm not too familiar with the STM32W.

What I can tell you is the 0x7F pattern is not checked by the boot loader on the STM32, it is used as a timing pattern, and based on the perceived timing it then sets a baud rate, and responds. What you see at the host side will depend on the accuracy or disparity in the baud rates at either end.

Now it's only checking for 0x7F timing pattern at initial start up, after it has the baud rate, it will most likely respond to subsequent 0x7F's with a NACK. Try sending some other identification commands. The pattern also assumes 8-bit, Even Parity, 1 Stop bit. As best I can tell the STM32W uses the same serial protocol with the BOOTx straps as the other members of the family. I'm looking for a clear cite right now.

On the application side, you could pretty much do what you want in terms of protocols. Using something like XMODEM,  HTTP or TFTP. The one key consideration is however that running from, and writing to the flash memory will cause significant stalling of the processor. To the point where peripherals will over/under run their buffers. Ideally running something from ROM or RAM to perform the update to avoid this problem.