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Cortex-M0: How to switch from one program to another

Hi,

In my Cortex-M0 project, there are two program images residing at different memory locations: 0x0000_0000 and 0x0010_0000.  Each program has its own vector table.  M0 will boot from the program at 0x0010_0000 then switch to the other program (0x0000_0000) at the end.

What is the correct way to switch to the porgram at 0x0000_0000?  I'm not sure whether the following instructions are correct or not.

     LDR     R6, =0x1                             ; set R6 to 0x0000_0001 due to Thumb mode

     LDR     R0, [R6]

     MOV     SP, R0

     LDR     R1, [R6, #4]

     BX      R1

Can someone please point me the right implementation?  Thanks a lot.

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  • Thanks jensbauer, So it is similar to bootloader app I guessed. Some MCUs have inbuilt bootloader, isn't it? I think STM32F4 has one.

    Also in this particular case, if VTOR is updated in the image #1, then it would later always execute image #2 when power cycled. It won't be able to get back to image #1 unless VTOR is again changed to vector table of image #1. 

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  • Thanks jensbauer, So it is similar to bootloader app I guessed. Some MCUs have inbuilt bootloader, isn't it? I think STM32F4 has one.

    Also in this particular case, if VTOR is updated in the image #1, then it would later always execute image #2 when power cycled. It won't be able to get back to image #1 unless VTOR is again changed to vector table of image #1. 

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