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STM32 UART1 interrupts not firing after booatloader to user application jump

Jamie Campbell

Hi Everyone.

I have been trawling these forums reading about the bootloader code in AN2557, looking for an answer to a problem I have.

I have the bootloader up and running, and I can download my user application code via RS232 USART1. The flash programs and verifies correctly, and the PC jumps to my user application code. I can see data being piped out of USART1, so i know my code is running correctly. The bootloader code is at 0x08000000, and my application code is at 0x08002000. I have set VECT_TAB_OFFSET to 0x00002000 and I am calling SystemInit from my user application main().

However, I do not receive data on USART1 once my application code is running. All the settings for the port are the same as the bootloader, but just in case I have tried DeIniting it before initialising in my application code. Important to note that the Bootloader code doesn't use USART1 interrupts - it just polls.

I am calling NVIC_SETPRIMASK() before jumping to application code, and NVIC_RESETPRIMASK() in my applicaton code main();

I have also tried NVIC_GenerateSystemReset() instead of jumping to my code, and still I don't get data received correctly. It's driving me mad!

If I load up my bootloader and application code into flash through uVision4, and run, I get interrupts and can receive data on USART1. The problem occurs when the bootloader code is running, then the flash is update and the PC jumps (or chip is reset) and the application code runs.

What seems to be happening is this: After the user code starts execution, I get a USART1 interrupt. The flags are:

SR : CTS = 0, LBD = 1, TXE = 1, TC = 1, RXNE = 1, IDLE = 1, ORE = 1, NE = 0, FE = 0, PE = 0

RXNEIE = 1

And then if I try to step over the following line of code in my USART1 IRQ handler, the code window gets out of step.

if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)

My application code still spews data form USART 1, but then eventually I will get an error in uVision, trying to read data from addresses that are in the bootloader code range, such as 0x080002xx.

Any tips greatly appreciated.

Thanks.

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