I'm working on a project using a STM32105 microcontroller. An RTX application is loaded at 0x8020000 while a secondary bootloader is loaded at 0x8000000. Transferring execution to the application from the bootloader works as expected, however after initialization in the main is completed and a call is made to os_sys_init, the system is off in the weeds. Specifically, os_sys_init calls the SVC Handler through the SVC instruction. Instead of vectoring to 0x80201CC as expected it seems like the offset of the RTX application is ignored and vectors to 0x80001CC. Note that when my RTX application is run at 0x8000000 without a secondary bootloader it runs correctly. The secondary bootloader is currently a stripped down version of my RTX application without RTX, and with only a vector to my RTX application at 0x8020000. Any idea why the upper two bytes of the SVC Handler address would be ignored?
Here's the main from the secondary bootloader code:
/*---------------------------------------------------------------------------- main program *----------------------------------------------------------------------------*/ int main (void) { /* execution starts here */
// Need to reset USART1 and RCC before jumping to bootloader RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, ENABLE); RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, DISABLE); RCC_DeInit();
JumpAddress = *(__IO uint32_t*) (ApplicationAddress + 4); Jump_To_Application = (pFunction) JumpAddress; /* Initialize user application's Stack Pointer */ __set_MSP(*(__IO uint32_t*) ApplicationAddress); Jump_To_Application();
while (1) {} }
See posting instructions when putting source code into a message, then review in the preview.
Make sure you are setting the Vector Table Address register to the correct base address, this is often done in the SystemInit() code. Check the value in SCB->VTOR
That was it. Thank you!