example_locate_access_eeprom.c

Mplab C30编译器

 /* Example illustrating how to locate and access data in EEPROM Memory*/

 /***********************************************************************
 *  Table1 is aligned to a 32-bit address, so it will be eligible for   * 
 *  erasing or programming using the row programming algorithm. Table2  * 
 *  is defined with standard alignment, so it must be erased or         *
 *  programmed one word at a time. The macro _EEDATA is used to place   *
 *  a variable in the Data EEPROM section of memory and align the       *
 *  variable to the specified byte boundary. This macro is defined in   *
 *  all the processor header files, except the ones that don't have     *
 *  data flash. This example is targeted for the dsPIC30F6014 processor,*
 *  and includes the processor header file p30f6014.h or optionally     *
 *  p30fxxxx.h.                                                         *
 *                                                                      * 
 *  The compiler and linker treat Data EEPROM like any other custom-    *
 *  defined (psv) section. The compiler will not set the PSV bit in the *
 *  CORCON register or set the PSVPAG to access Data EEPROM; you must   *
 *  perform these tasks manually. Once the PSV bit and PSVPAG are set   *
 *  for Data EEPROM, the compiler can freely access any variables stored*
 *  there. As this example shows, you can use the __builtin_psvpage()   *
 *  and __builtin_psvoffset() helper functions for variables stored     *
 *  in Data EEPROM.                                                     *
 *                                                                      *
 *  If an application stores constants in the compiler-managed PSV      *
 *  section of program memory (auto_psv) and Data EEPROM, the compiler  *
 *  will set the PSV bit in the CORCON register and set PSVPAG for      *
 *  the compiler-managed PSV section on startup (in crt0.s). You must   *
 *  manually modify PSVPAG to access Data EEPROM. Namely, the original  *
 *  PSVPAG must be saved before the access, and then restored after the *
 *  access.                                                             *
 *                                                                      *
 *  Note 1: When placing variables in Data EEPROM, the const qualifier  *
 *          is optional.                                                *
 *       2: The ((address ( ))) attribute can be used to locate         *
 *          variables in Data EEPROM to a specific address.             *
 *                                                                      *
 *                                                                      *
 *  For additional information about dsPIC architecture and language    *
 *  tools, refer to the following documents:                            *
 *                                                                      *
 *  MPLAB C30 Compiler User's Guide                        : DS51284    *
 *  dsPIC 30F MPLAB ASM30, MPLAB LINK30 and Utilities                   *
 *                                           User's Guide  : DS51317    *
 *  Getting Started with dsPIC DSC Language Tools          : DS51316    *
 *  dsPIC 30F Language Tools Quick Reference Card          : DS51322    *
 *  dsPIC 30F 16-bit MCU Family Reference Manual           : DS70046    *
 *  dsPIC 30F Programmer's Reference Manual                : DS70030    *
 *                                                                      *
 *  Example file has been compiled with MPLAB C30 v1.30.00              *
 *                                                                      *
 ************************************************************************
 *                                                                      * 
 *    Author:                                                           *
 *    Company:                                                          * 
 *    Filename:       Ex_Locate_Access_EEPROM.c                         *
 *    Date:           02/01/2005                                        *
 *    File Version:   1.00                                              *
 *    Other Files Required: p30f6014.gld                                *
 *    Tools Used: MPLAB IDE -> 7.01.00                                  *
 *                Compiler  -> 1.30.00                                  *
 *                Assembler -> 1.30.00                                  *
 *                Linker    -> 1.30.00                                  *
 *                                                                      *
 ***********************************************************************/

 /* Include the appropriate header (.h) file, depending on device used */
 /* Example (for dsPIC30F5013): #include <p30f5013.h>                  */
 /* Alternatively include the generic header file, p30fxxxx.h, as shown 
    below.                                                              */

	/* load SFR definitions and macros */
	#include "p30fxxxx.h"


unsigned int _EEDATA(32) Table1[16]={0};
unsigned int _EEDATA(2) Table2[4]= {0x1234, 0x5678, 0x9ABC, 0xDEF0};

unsigned int *ee_rd_ptr;
unsigned int temp_data[4];


int main( void )
{
	/* enable the PSV window since no program constants 
	   are stored in program memory */
	CORCONbits.PSV = 1;

	/* set the PSV page using a built-in function */
	PSVPAG = __builtin_psvpage(&Table2);

	/* initialize EEPROM read pointer using a built-in function */
	ee_rd_ptr = (unsigned int *) __builtin_psvoffset(&Table2);

	/* read integer data from EEPROM */
	temp_data[0] = *ee_rd_ptr++;
	temp_data[1] = *ee_rd_ptr++;
	temp_data[2] = *ee_rd_ptr++;
	temp_data[3] = *ee_rd_ptr;

	while ( 1 );
}


/*  The equivalent array definitions for Table1 and Table2 in assembly language appear
    below. Use of * as a section name causes the assembler to generate a unique name
    based on the source file name.

       .global _Table1
       .section *,eedata
       .align 32
_Table1:
       .space 32

       .global _Table2
       .section *,eedata
       .align 2
_Table2:
       .word 0x1234
       .word 0x5678
       .word 0x9ABC
       .word 0xDEF0   */