I'm hoping for the collective knowledge here, as I get stuck at my current project... I'm trying to implement an update function for the application program on a PIC32CZ8110CA... µC.

The following problem:

• I'm using the µC without having written my own bootloader.
• I would like to receive the new program code during normal program execution and write it to the second application flash bank. That works so far.
• Now the new program code is verified and then the µC is ready for the bank swap and a restart.
• After the restart, the new program should run.

But I'm stuck at point with the bank swap. I think I'm setting the right bit, but after a restart the old program continues to run as if nothing had happened.

I had a similar problem with an ATSAMD51, and I was told that the function for the bank swap had to be a RAMFUNC. In retrospect, that sounds logical and it worked there too. That doesn't seem to be the problem with the PIC32CZ.

Here are the relevant parts of my code:

else if(rx_cfg_buffer[rx_cfg_gi].DATA[3] == 0x0F) // Firmwareupdate 
{
    if(rx_cfg_buffer[rx_cfg_gi].DATA[2] == 0x01)
    {
        firmware_msg_cnt = (uint32_t)((rxTestbuffer_8Bit[7+8]<<24) |  rxTestbuffer_8Bit[6+8]<<16) | (rxTestbuffer_8Bit[5+8]<<8) | rxTestbuffer_8Bit[4+8]);
        clean_rx_cfg_reply_data();
        rx_cfg_reply.ID = rx_cfg_buffer[rx_cfg_gi].ID+1;
        rx_cfg_reply.DATA[2] = 0x00;
        rx_cfg_reply.DATA[3] = 0x0F;
        rx_cfg_reply.DATA[4] = FIRMWAREUPDATE_MSG_LIMIT;
        send_cfg_reply();
        // Flashbereich löschen                        
        panel2_firmware_erase(firmware_msg_cnt);
        // Neue Firmware abholen                        
        get_firmware(firmware_msg_cnt);
        // Prüfen neue Firmware
        verify_firmware(firmware_msg_cnt);
        // Bank-Swap
        volatile uint32_t current_panel = ((FCW_REGS->FCW_SWAP & FCW_SWAP_PFSWAP_Msk) >> FCW_SWAP_PFSWAP_Pos);
        if(current_panel == 1)
            FCW_ProgramFlashBankSelect(0);
        else 
            FCW_ProgramFlashBankSelect(1);
        }
    }

#define    PROGRAM_FLASH_BANK_1    (0U)
#define    PROGRAM_FLASH_BANK_2    (1U)
#define __ramfunc__ __attribute__ ((section(".ramfunc"), unique_section, noinline))

typedef uint32_t PROGRAM_FLASH_BANK;

typedef enum
{
    FCW_UNLOCK_WRKEY = 0x91C32C01,
    FCW_UNLOCK_SWAPKEY = 0x91C32C02,
    FCW_UNLOCK_CFGKEY = 0x91C32C04
}FCW_UNLOCK_KEY;

static void FCW_UnlockSequence(FCW_UNLOCK_KEY key)
{
    FCW_REGS->FCW_KEY = (uint32_t)key;
}

__ramfunc__ void FCW_ProgramFlashBankSelect(PROGRAM_FLASH_BANK pfmBank)
{
    while(((FCW_REGS->FCW_STATUS & FCW_STATUS_BUSY_Msk)) != 0U)
    {
        /* Do Nothing */
    }
    FCW_UnlockSequence(FCW_UNLOCK_SWAPKEY);
    if (pfmBank == PROGRAM_FLASH_BANK_1)
    {
        FCW_REGS->FCW_SWAP &= (~FCW_SWAP_PFSWAP_Msk);
    }
    else
    {
        FCW_REGS->FCW_SWAP |= (FCW_SWAP_PFSWAP_Msk);
    }
}

Here is the link to the data sheet: .html

Best regards and many thanks, Fabian