PIC24FV32KA304 datasheet(68/364 Pages) MICROCHIP

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PIC24FV32KA304 FAMILY

DS39995D-page 68

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6.4.3

READING THE DATA EEPROM

To read a word from data EEPROM, the table read

instruction is used. Since the EEPROM array is only

16 bits wide, only the TBLRDL instruction is needed.

The read operation is performed by loading TBLPAG

and WREG with the address of the EEPROM location,

followed by a TBLRDL instruction.

A typical read sequence, using the Table Pointer

management

(builtin_tblpage

and

builtin_tbloffset) and table read procedures

(builtin_tblrdl) from the C30 compiler library, is

provided in Example 6-5.

Program Space Visibility (PSV) can also be used to

read locations in the data EEPROM.

EXAMPLE 6-5:

READING THE DATA EEPROM USING THE TBLRD COMMAND

int __attribute__ ((space(eedata))) eeData = 0x1234;

int data;

// Data read from EEPROM

/*--------------------------------------------------------------------------------------------

The variable eeData must be a Global variable declared outside of any method

the code following this comment can be written inside the method that will execute the read

----------------------------------------------------------------------------------------------

unsigned int offset;

// Set up a pointer to the EEPROM location to be erased

TBLPAG = __builtin_tblpage(&eeData);

// Initialize EE Data page pointer

offset = __builtin_tbloffset(&eeData);

// Initizlize lower word of address

data = __builtin_tblrdl(offset);

// Write EEPROM data to write latch

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