Texas Instruments MSC1210 manual Flash Memory as Data Memory

Flash Memory as Data Memory

15.5 Flash Memory as Data Memory

If so configured in HCR0, some portion of flash memory can be accessed by your application program as flash data memory. The amount of flash memory that is partitioned as flash data memory is controlled by the low 3 bits of HCR0. Please see Section 15.1.1.1, Hardware Configuration Register 0, for details.

When some amount of flash memory is partitioned as flash data memory, the program may read, update, and store information in nonvolatile memory that will survive power-off situations. That makes the flash data memory a useful area to store configuration or data logging information.

The following program illustrates how flash data memory may be read and up- dated.

Note:

The MSEC and USEC SFRs must be correctly set prior to erasing or writing to flash memory.

Within the infinite while() loop, the program first reads flash data memory. This is accomplished directly by reading XRAM memory. This is accomplished in this C program by using the pFlashPage pointer—it is accomplished in assembly language using the MOVX instruction.

After reading flash memory, it increments the value of the first byte of the memory block read by one. The call to page_erase()is a call to the routine in boot ROM that erases the requested block of memory. Thereafter, it makes re- peated calls to write_flash_chk to write the buffer back to the block of flash data memory one byte at a time.

The infinite loop continues by displaying the result of the writes to flash data memory (0 = Success) and the updated value contained in the buffer as read from flash data memory via the pFlashPage pointer. It then prompts the user to hit any key, after which the loop will repeat itself and the first byte of the buffer will again be incremented.

#include <stdio.h> #include <reg1210.h> #include ”rom1210.h”

//define the page we want to modify #define PAGE_START 0x0400

#define PAGE_SIZE 0x80

//define a pointer to this page char xdata * pFlashPage;

//define a RAM area as a buffer to hold one page char xdata Buffer[PAGE_SIZE];

int main()

{

char Result;

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