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    • Change application on Reset !

    Posted by thomasfuture on 2018-05-28 14:04

    Hi Tarek,

    Yes, each applications have its Reset Handler, but maybe this is not the way to do this, if you can help me on this it's will be cool.

    Regards

    Reads: 2425
    Posted by tarek bouchkati on 2018-05-28 14:12 Tunisia

    In that case, this could be a solution :

    Copy to clipboard
    SwapApp:
  ldr r0, =0x08019F40
  bx  r0

Reset_Handler:  
  /* boot swap management */
  ldr r0, =0x20000270
  ldr r1, =0xFEED0001
  ldr r2, [r0]
  cmp r1, r2
  bne SwapApp
  /* end of boot swap management */

  ldr   sp, =_estack      /* set stack pointer */
  ........
         Posted by thomasfuture on 2018-05-28 15:26

    So, if I follow what’s you saids, I don’t need to touch to SP et PC ?


    I try with your code, but without success, or only half !

    When I do a Reset, I switch from App1 to App2 but afterthe program loop in main of App2..

    Posted by tarek bouchkati on 2018-05-28 16:08 Tunisia

    I've tested the solution without issues.
    So, I will share with you a complete example tomorrow 😊

         Posted by thomasfuture on 2018-05-28 16:58
    Thanks Tarek because I didn't see the issue here..
    Posted by tarek bouchkati on 2018-05-28 22:57 Tunisia

    Look, while driving home, I have remembered that STM32L072CZ has dual bank boot capability, so this could be achieved by changing dynamically the the BFB2 option bit.
    This could be a cutting edge solution !

    Back to the first one, the pb could be that we jumbed directly to the App2' main.
    So, could you verify that 0x08019F40 is really the App2 Reset Handler Address ?

         Posted by thomasfuture on 2018-05-29 09:20

    App2 address is now 0x08018000 (not 0x08019F40), and 0x08018000 it's first address of bank 1.

    From .map file :

    .text.Reset_Handler
    0x08023534 0x50 Projects/SW4STM32/startup_stm32l072xx.o
    0x08023534 Reset_Handler

    So we need to jump to 0x08023534, in order to init memory, system and go to main.

    Posted by tarek bouchkati on 2018-05-29 12:40 Tunisia

    In that case :

    Copy to clipboard
    SwapApp:
  ldr r0, =0x08023534
  bx  r0

Reset_Handler:  
  /* boot swap management */
  ldr r0, =0x20000270
  ldr r1, =0xFEED0001
  ldr r2, [r0]
  cmp r1, r2
  bne SwapApp
  /* end of boot swap management */

  ldr   sp, =_estack      /* set stack pointer */
  ........
         Posted by thomasfuture on 2018-05-29 14:03

    In cortex M0+ it's not BNE but BEQ

    -> Suffix : EQ Flags : Z = 1 Meaning : Equal, last flag setting result was zero.

    From The STM32L0 Cortex-M0+ instruction set 😊

    So made this :

    /* boot swap management */

    ldr r4, =0x20000000 //load address of the value stored in .c
    ldrb r5, r4 //load in r5 value stored in .c
    ldr r6, =0xFEED0001 //to compare
    cmp r5, r6 //compare value from .c (store in RAM) to r6 (fixed value)
    beq SwapApp //if equal Reboot from App2
    /* end of boot swap management */


    ldr r0, =_estack
    mov sp, r0 /* set stack pointer */
    /* Copy the data segment initializers from flash to SRAM */
    movs r1, #0

    b LoopCopyDataInit

    SwapApp:
    ldr r0, =0x08023534
    bx r0


     
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