simple_flash_example.c

A simple example of run time self programming - reads/writes a single 16-bit value to flash.

 
#include "pic24_all.h"
#include <stdio.h>

#if (defined(__PIC24F__) || defined(__PIC24E__) || defined(__dsPIC33E__))
# warning "For all PIC24F and some PIC24E/dsPIC33E family members, the DATA_FLASH_PAGE is set to the second to last flash page instead of the last page,"
# warning "as the last flash page in the 24F family contains the configuration bits."
#endif


#if defined(__PIC24HJ64GP502__) || defined(__PIC24FJ64GA002__)
# define LAST_IMPLEMENTED_PMEM 0x00ABFF
#elif defined(__PIC24HJ32GP202__) || defined(__PIC24FJ32GA002__) || defined(__dsPIC33FJ32GP202__)
# define LAST_IMPLEMENTED_PMEM 0x0057FF
#elif defined(__dsPIC33FJ128GP802__)
# define LAST_IMPLEMENTED_PMEM 0x0157FF
#elif defined(__PIC24EP64GP202__)               // test PIC24E device
# define LAST_IMPLEMENTED_PMEM 0x00AFFF
#elif defined(__dsPIC33EP64GP502__) || defined(__dsPIC33EP64GP503__) || defined(__dsPIC33EP64GP504__) || defined(__dsPIC33EP64GP506__)
# define LAST_IMPLEMENTED_PMEM 0x00AFFF
#elif defined(__dsPIC33EP128GP502__) || defined(__dsPIC33EP128GP504__) || defined(__dsPIC33EP128GP506__)
# define LAST_IMPLEMENTED_PMEM 0x0157FF
#elif defined(__dsPIC33EP256GP502__) || defined(__dsPIC33EP256GP504__) || defined(__dsPIC33EP256GP506__)
# define LAST_IMPLEMENTED_PMEM 0x02AFFF
#elif defined(__dsPIC33EP512GP502__) || defined(__dsPIC33EP512GP504__) || defined(__dsPIC33EP512GP506__)
# define LAST_IMPLEMENTED_PMEM 0x0557FF
#else
# error "Define LAST_IMPLEMENTED_PMEM for your processor!"
#endif


//calculate starting address of a flash page to store data
//some PIC24H/dsPIC33 store configuration bits on last page, so skip that
#if (defined(__PIC24F__) || defined(__PIC24E__)|| defined(__dsPIC33E__))
# define DATA_FLASH_PAGE (((LAST_IMPLEMENTED_PMEM/FLASH_PAGESIZE)*FLASH_PAGESIZE)-FLASH_PAGESIZE)  //2nd to last page of flash
#endif
#if (defined(__PIC24H__) || defined(__dsPIC33F__))
# define DATA_FLASH_PAGE ((LAST_IMPLEMENTED_PMEM/FLASH_PAGESIZE)*FLASH_PAGESIZE)  //last page of flash
#endif



typedef struct _REC {
  uint16_t u16_val;     //single 16-bit value
} REC;

#define NUM_ROWS (((sizeof(REC))/FLASH_ROWBYTES) + 1)
#define FLASH_DATA_SIZE (NUM_ROWS*FLASH_ROWBYTES)

typedef union _UFDATA {
  REC  dat;
  char fill[FLASH_DATA_SIZE];  //worst case allocates extra row, but ensures RAM data block is multiple of row size
} UFDATA;

UFDATA fdata;

void doCommit(UFDATA* p_ufdata) {
  union32 u_memaddr;
  u_memaddr.u32 = DATA_FLASH_PAGE;
  doWritePageFlash(u_memaddr, (uint8_t *) p_ufdata, FLASH_DATA_SIZE);
}

void doRead(UFDATA* p_ufdata) {
  union32 u_memaddr;
  u_memaddr.u32 = DATA_FLASH_PAGE;
  doReadPageFlash(u_memaddr, (uint8_t *) p_ufdata, FLASH_DATA_SIZE);
}


uint8_t printMenu() {
  printf("1 Read 16-bit value from flash.\n");
  printf("2 Write 16-bit value to flash. \n");
  printf(" Enter number (1-2): ");
  return inCharEcho();
}

void doMenu() {
  uint8_t u8_c;
  char data[32];
  uint16_t u16_val;
  u8_c = printMenu();
  printf("\n");
  switch(u8_c) {
    case '1':
      doRead(&fdata);
      printf("The 16-bit value read from memory is: %u (%x hex)\n",fdata.dat.u16_val,fdata.dat.u16_val);
      break;
    case '2':
      printf("Enter 16-bit value+\\n (0 to 65535, decimal): ");
      inStringEcho(data,31);
      sscanf(data,"%d", (int *) &u16_val);
      fdata.dat.u16_val = u16_val;
      doCommit(&fdata);  //write the data
      break;
  }
}

int main (void) {
  configBasic(HELLO_MSG);
  while(1) {
    doMenu(1);
  } //end while
}//end main