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

wshen

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.

Parents
  • 0 in reply to Gopal Amlekar

    Changing VTOR isn't permanent; it's just like any other hardware register, and has a default on startup.

    -So power-cycling will always execute image#1 in this particular case.

    Most microcontrollers have a boot-ROM, yes. This makes it possible to program the devices in other ways than JTAG and SWD, for instance via UART or USB, but this of course depends on the boot-ROM code.

Reply
  • 0 in reply to Gopal Amlekar

    Changing VTOR isn't permanent; it's just like any other hardware register, and has a default on startup.

    -So power-cycling will always execute image#1 in this particular case.

    Most microcontrollers have a boot-ROM, yes. This makes it possible to program the devices in other ways than JTAG and SWD, for instance via UART or USB, but this of course depends on the boot-ROM code.

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