struct info_mem_s
{
union
{
struct nv_parms_s s;
int8_t x[128];
} seg_a;

struct nv_parms_s
{
int16_t variable;
}

void flash_write_int16(int16_t *ptr, int16_t value)
{
_DINT();
FCTL3 = FWKEY; /* Lock = 0 */
FCTL1 = FWKEY | WRT;
*((int16_t *) ptr) = value; /* Program the flash */
}

flash_write_int16((int *) &(nv_parms.seg_a.s.variable), (int16_t)1000);

// ***********************************************************************
// This routine makes the flash looks like EEPROM. It will erase and
// replace just one word
// This routine copies will erase SEGA and then image SEGB to SEGA
// It will then erase SEGB and copy from SEGA back to SEGB all 128 bytes
// except the one to be replaced.
// ***********************************************************************
void flash_replace16(int16_t *ptr, int16_t word)
{
int *read_ptr;
int *write_ptr;
int w;

//Optimise the case where the new and old values are the same
if (*ptr == word)
return;
flash_clr((int *) FSEG_A);

_DINT();
//Set to write mode to prepare for copy
FCTL3 = FWKEY; /* Lock = 0 */
FCTL1 = FWKEY | WRT;

//Copy block B to A
read_ptr = (int *) FSEG_B;
write_ptr = (int *) FSEG_A;
for (w = 0; w < 64; w++)
*write_ptr++ = *read_ptr++;
flash_clr((int *) FSEG_B);

//Set to write mode to prepare for copy
FCTL3 = FWKEY; /* Lock = 0 */
FCTL1 = FWKEY | WRT;

//Copy block A to B, slipping in the new value at the right location
read_ptr = (int *) FSEG_A;
write_ptr = (int *) FSEG_B;
for (w = 0; w < 64; w++, read_ptr++, write_ptr++)
{
if (write_ptr == ptr)
*write_ptr = word;
else
*write_ptr = *read_ptr;
}
flash_secure();
_EINT();
}

#define __infomem___ Pragma("location=\"INFO\"")

__infomem__ const struct info_mem_s nv_parms

flash_write_int16((int *) &(nv_parms.seg_a.s.variable), nv_parms.seg_a.s.variable & ~(1 << 2));