The Flash memory module of the MSP430 Flash type single-chip microcomputer is divided into several segments according to different capacities, of which information storage segmenga and segmentb have 128 bytes, and other segments have 512 bytes. The address of SegmentB is: 0x01000H to 0x107F, the address of Segmenta is: 0x01080H to 0x010ffH. The addresses of other segments are different from 0xffff, and each 512 bytes are assigned.
When the Flash memory is written, each bit can only be turned "0" by "1", and cannot be "0" to "1", so when we have data to be saved to the Flash memory, you must first The segment performs the entire erase operation, and the erase operation makes the corresponding segment Flash memory into full "1". Below is a subroutine that erases the flash segment, and after configuring the necessary registers, write the data in the segment, and erase a segment.
Void Flash_CLR (INT * PTR)
{
_Dint (); // off interrupt
FCTL3 = 0x0a500; // * Lock = 0 unlock
FCTL1 = 0x0a502; // * ERASE = 1 enable erasure
* ((Int *) PTR) = 0; // * Erase segment
}
Flash memory can be written according to byte or by word.
// byte writing
Void Flash_Write_INT8 (INT8_T * PTR, INT8_T VALUE)
{
_Dint ();
FCTL3 = 0x0a500; // Lock = 0 unlock
FCTL1 = 0x0A540; // Write = 1 enable written
* (INT8_T *) PTR) = value; // Write data
}
// word writing
Void Flash_Write_INT16 (INT16_T * PTR, INT16_T VALUE)
{
_Dint ();
FCTL3 = 0x0a500; / * Lock = 0 * /
FCTL1 = 0x0A540; / * Write = 1 * /
* ((Int16_t *) PTR) = value; / * Program the Flash * /
}
Flash memory can be written continuously
/ / Write the specified number of data by byte
Void Flash_Memcpy (Char * Ptr, Char * from, INT LEN)
{
_Dint ();
FCTL3 = 0x0a500; / * Lock = 0 * /
FCTL1 = 0x0A540; / * Write = 1 * /
While (len)
{
* PTR ++ = * from ++;
Len -;
}
}
In our application, you can save the data to be saved in a custom structure, for example:
Typedef struct setup
{
FLOAT GAIN_CH0; // 0 channel gain
FLOAT GAIN_CH1; // 1 channel gain
FLOAT GAIN_CH2; // 2 channel gain
...
CHAR INIT_FLAG; // Initialization marker, constant to 0xAA;
} Setup;
We define a setup structure, store the gain of three AD channels, and other information to be saved, the role of init_flag is whether the parameters of the flag flash have been properly initialized, when we set the flash parameter, set the init_flag The fixed value, for example, set to 0xaah, check the init_flag when the program starts running, when the value of the init_flag is 0xaah, indicating that the parameters have been initialized.
Use flash parameters: Define a setup type pointer variable in the program, access the parameters in Flash by this pointer. E.g:
#Define segmenta 0x1080
Float Temp;
Setup * p_setup_flash = (setup *) Segmenta
IF (p_setup_flash- "init_flag == 0xAA)
{
Temp = p_setup_flash- "gain_CH0;
}
Modify FLASH information: Since Flash cannot be directly modified as RAM, you can copy Flash information to the RAM. After modifying the corresponding parameters, re-saved to the Flash memory before you first erase the Flash storage area. E.g:
Setup * p_setup;
Setup buf; // Temporary variable
P_setup = (setup *) segmenta // pointing to Flash
Memcpy (Char *) BUF, (char *) p_setup_flash, sizeof (setup)); // Copy to RAM
P_setup = // Pointing RAM
P_setup- "GAIN_CH0 = 1.02; // Modify parameters
Flash_memcpy ((char *) p_setup_flash, (char *) BUF, SIZEOF (SETUP)); // Copy to Flash, Technology Zone
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