Erasing external flash memory (MCF51EM256 microcontroller)

Question

I'm working with a MCF51EM256 Freescale microcontroller and I've some problems to erase the external flash memory (0x20000 - 0x2FFFF).

This is my main program:

void main(void) {
  EnableInterrupts;

  FlashInit();

  DisableInterrupts;
  EraseFlash(0x020000);
  EraseFlash(0x020800);
  EraseFlash(0x020C00);
  EnableInterrupts;

  for(;;) {
    __RESET_WATCHDOG(); /* feeds the dog */
    SetLED(2, 2);       // Toggle led if the program is running
  } /* loop forever */
  /* please make sure that you never leave main */
}

Where "EraseFlash()" :

void EraseFlash(long addr){
    // The flash sector to erase is always 1 kB

    long eraseValue = 0xFFFFFFFF;
    Flash_Cmd((unsigned long)addr, 1, &eraseValue, 0x40);
}

And "Flash_Cmd()" :

#define FLASH_MASS_ERASE_CMD  0x41
#define FLASH_ERASE_CMD       0x40
#define FLASH_PROGRAM_CMD     0x20
#define FLASH_BURST_CMD       0x25

UINT8 /*far*/ 
Flash_Cmd(UINT32 FlashAddress, 
      UINT16 FlashDataCounter, 
      UINT32 *pFlashDataPtr, 
      UINT8 FlashCommand)
{
  /* Check to see if FACCERR or PVIOL is set */
  if (FSTAT &0x30)  
  {         
      /* Clear Flags if set*/
      FSTAT = 0x30;  
  }

  if (FlashDataCounter)
  {
    do
    {
        /* Wait for the Last Busrt Command to complete */
        while(!(FSTAT&FSTAT_FCBEF_MASK)){};/*wait until termination*/

        /* Write Data into Flash*/
        (*((volatile unsigned long *)(FlashAddress))) = *pFlashDataPtr;
        FlashAddress += 4;
        pFlashDataPtr++;

        /* Write Command */
        FCMD = FlashCommand;

        /* Put FCBEF at 1 */
        FSTAT = FSTAT_FCBEF_MASK;

        asm (NOP);
        asm (NOP);
        asm (NOP);

         /* Check if Flash Access Error or Protection Violation Error are Set */
        if (FSTAT&0x30)
        {     
          /* If so, finish the function returning 1 to indicate error */
          return (1);
        }

    }while (--FlashDataCounter);
  }
  /* wait for the last command to complete */
  while ((FSTAT&FSTAT_FCCF_MASK)==0){};/*wait until termination*/

  /* Return zero to indicate that the function executed OK */
  return (0);
}

My main never reaches the for(;;) loop, because is blocked by the 3th call to EraseFlash().

If I put only two or less calls, it works. Example:

void main(void) {
  EnableInterrupts;

  Platform_GPIO_Init();
  FlashInit();

  DisableInterrupts;
  EraseFlash(0x020000);
  EraseFlash(0x020800);
  EnableInterrupts;

  for(;;) {
    __RESET_WATCHDOG(); /* feeds the dog */
    SetLED(2, 2);       // Toggle led if the program is running
  } /* loop forever */
  /* please make sure that you never leave main */
}

Can someone tell me what I'm doing wrong? I also tryed with other flash memory address and without interrupts disabling and its the same.

Edit: Both calls return 0, which means the function executed OK

Thank you all!

Answer 1

I've checked the datasheet and changed the FLASH_CLOCK in the header of my flash driver:

(SYSTEM_CLOCK/200000) to (SYSTEM_CLOCK/400000)

Before:

#if (SYSTEM_CLOCK/2) > 12800000 /* 12.8 MHz */
    #define FLASH_CLOCK (UINT8)(( (SYSTEM_CLOCK/3200000) -1) | 0x40)
#else
    #define FLASH_CLOCK (unsigned char)( (SYSTEM_CLOCK/200000) -1)//<200KHz
#endif

Now:

#if (SYSTEM_CLOCK/2) > 12800000 /* 12.8 MHz */
    #define FLASH_CLOCK (UINT8)(( (SYSTEM_CLOCK/3200000) -1) | 0x40)
#else
    #define FLASH_CLOCK (unsigned char)( (SYSTEM_CLOCK/400000) -1)//<200KHz
#endif

Finally my program works.