CCS/MSP430FR2422: TLV structure checksum?

Hi Victor,

You can try the Peripherals Example for CRC. I would also suggest you to go through the CRC chapter of the device User's Guide for how to use the CRC module of MSP430.

Here is the example code that you suggested, as applied to the TLV CRC:

uint16_t acc;

// Software algorithm - CCITT CRC16 code
unsigned int CCITT_Update(unsigned int init, unsigned int input)
{
  unsigned int CCITT;
  CCITT =(unsigned char)(init >> 8)|(init << 8);
  CCITT ^= input;
  CCITT ^= (unsigned char)(CCITT & 0xFF) >> 4;
  CCITT ^= (CCITT << 8) << 4;
  CCITT ^= ((CCITT & 0xFF) << 4) << 1;
  return CCITT;
}

// Check TLV area of information flash
bool tlv_check(void)
{
  unsigned i;

  CRCINIRES = 0xffff;
  for (i = 0x01a04; i < 0x01af0; i += 2)
  {
    uint16_t a = *(uint16_t*) i;
    CRCDIRB = a;
  };

  uint16_t acc = 0xffff;
  for (i = 0x01a04; i < 0x01af0; i += 1)
    acc = CCITT_Update(acc, *(uint8_t*) i);

  while (1);
}

Both the software update function and the hardware CRC module calculate the same value -- on my CPU, an MSP430FR2422, this is 0x0D46. My TLV structure is this, spanning 0x1A00 through 0x1AEF:

0x1A00: 0606 0571 8311 1010 0A08 27E2 2DF1 0018
0x1A10: 0046 FEFC 0811 8011 0000 02C3 0348 0412
0x1A20: 7FF9 014B FFFF FFFF FFFF FFFF FFFF FFFF
0x1A30: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A40: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A50: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A60: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A70: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A80: FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF
0x1A90: 0110 965E 011A 0000 0110 96B7 0118 010E
0x1AA0: 011A 5800 0110 96B8 0114 0010 0110 965E
0x1AB0: 0112 0000 0110 9614 0112 0000 0116 0600
0x1AC0: 0110 9601 011E 9000 0110 961D 0112 0040
0x1AD0: 0116 6B64 0110 9602 0116 8CAC 0118 BB30
0x1AE0: 0114 0C27 0154 02D2 1A90 0001 F982 3CC3

As you can see, the CRC stored in the structure at address 0x1A02 is 0x0571.

No matter how we compare 0x0D46 to 0x0571, byte reversed, bit reversed, or a combination, they don't match... Oops.

What am I missing?

Hi Victor,

Unfortunately I cannot provide any more answers, but I can provide the '430 team members another data point.

Steps Taken

I also tried repeating similar experiments on the MSP430FR5739, and came up with sadly the same results. I used the below modified code example to try a combination of data reversed, get results bits reversed, and memory ranges (0x1A04-0x1AFF, 0x1A04-0x1A7F) and cannot replicate the CRC value stored in the device's TLV area.

#include "driverlib.h"

void main (void)
{
    uint16_t crcSeed = 0xFFFF;
    uint16_t data[] = {0x0123,
                           0x4567,
                           0x8910,
                           0x1112,
                           0x1314};
    uint16_t crcResult;
    uint16_t i;

    //Stop WDT
    WDT_A_hold(WDT_A_BASE);

    //Set P1.0 as an output
    GPIO_setAsOutputPin(
        GPIO_PORT_P1,
        GPIO_PIN0);

    //Set the CRC seed
    CRC_setSeed(CRC_BASE,
        crcSeed);

    for (i = 0x1A04; i <= 0x1AFF; i++)
    {
        //Add all of the values into the CRC signature
        CRC_set16BitDataReversed(CRC_BASE,
            *(unsigned char*)(i));
    }

    //Save the current CRC signature checksum to be compared for later
    crcResult = CRC_getResult(CRC_BASE);


    //Enter LPM4, interrupts enabled
    __bis_SR_register(LPM4_bits);
    __no_operation();
}

Below is the memory data itself from my particular device: