AnsweredAssumed Answered

Calling stm32429I-Eval Bootloader

Question asked by smith.chuck on May 2, 2014
Latest reply on Oct 4, 2017 by Clive One
Hello, we are wanting to call the built-in bootloader from our application without manipulating the BOOT0/BOOT1 pins. I am trying to use the EVAL board to validate our method. The Users Manual for the Eval board does state:  "The RS-232 boot loader mechanism is not supported on the STM32429I-EVAL". There is no explanation of this statement. However, if I move the Boot0 switch on the eval board to 1 and power cycle, I am able to at least connect to the bootloader over RS-232 using the ST demo flash loader program. If I can get that far by calling the bootloader on the Eval board with the BOOT pins both at 0, I will call it a success until our hardware is ready.

I have tried both calling the bootloader from C code, using the method posted on Youtube, and also calling it from my startup assemble code, using the method Clive has suggested in the forum, as follows (I am using IAR):

;; Default interrupt handlers.
PUBWEAK Reset_Handler
LDR R0,=0x1FFF0000
LDR R1,[R0,#0]
LDR R0,[R0,#4]
BX R0            ;debugger shows 0x1FFF4ABF in R0 at this point

Unfortunately, both methods display the same behavior - I cannot connect to the bootloader using the demo program. If I use the debugger, I can hit a breakpoint at the start of the bootloader (at 0x1FFF4ABE) , and can trace through it until I get bored, but as soon as I hit run, I hit a breakpoint back at the BX R0 line above, as if a reset is occurring, or the bootloader is jumping back to the start of the application. This made me suspect the dual boot mode of the 429, but I used ST-Link to verify the BFB2 bit in the options byte is cleared, so no dual boot should be taking place.

Any ideas?