checksum.c

msp430-soft编译工具

/*
  This code shows implementation of a flash checksum for verifying integrity of
  the data.  In this example, a checksum is calculated at program start,
  covering two flash segments.  The checksum is stored in another segment of
  flash.  The device then goes to sleep.  Two input signals can interrupt
  the device.  One initiates a verify of the checksum, and flashes the LED
  several times if it's correct; if it's not correct, it disables interrupts
  and lights the LED steadily.  The other input signal deliberately corrupts
  the flash block.

  After the program is run, several transitions of the "check" input should
  cause the LED to flash.  After one transition of the "corrupt" input, the
  next iteration of "check" will cause the LED to light steadily.


                MSP430F1612
             -----------------
         /|\|              XIN|-
          | |                 |
          --|RST          XOUT|-
            |                 |

*/

#include <msp430x16x.h>

#define flashStart     0xFA00
#define flashEnd       0xFDFF
#define flashChecksum  0x1080

int verifyFlash(void);
void storeChecksum(void);

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer
  FCTL2 = FWKEY + FSSEL0 + FN0;             // MCLK/2 for flash timing generator

  // .
  // .  Flash writes
  // .

  storeChecksum();

  // Later in the program....

  if (!verifyFlash())
  {
    // Handle the error
  }

  _BIS_SR(LPM3_bits+GIE);                   // Sleep until port interrupt
}

int verifyFlash(void)
{
  unsigned int i, checksum=0, storedChecksum;

  for (i=0;i<0x0200;i++)                  // Calculate checksum
    checksum += ((unsigned int *)flashStart)[i];

  storedChecksum = *(unsigned int *)flashChecksum; //Pull stored val from flash

  if (checksum==storedChecksum)           // Compare and return the result
    return(1);
  else
    return(0);
}


void storeChecksum(void)
{
  unsigned int i, checksum=0,*pFlashData;

  for (i=0;i<0x0200;i++)                    // Calculate checksum
    checksum += ((unsigned int *)flashStart)[i];

  // Erase checksum storage location
  pFlashData = (unsigned int *) flashChecksum; // Reset ptr to start of block
  FCTL3 = FWKEY;                            // Unlock flash
  FCTL1 = FWKEY + ERASE;                    // Set Erase bit
  *pFlashData = 0x0000;                     // Dummy write to erase

  // Store checksum
  FCTL1 = FWKEY+WRT;                        // Enable flash write
  *pFlashData = checksum;                   // Write checksum to flash
  FCTL3 = FWKEY + LOCK;                     // Lock flash
}