// EE_SV.C

//

// Illustrates how to save a quantity to and fetch a quantity from

// EEPROM.

//

// Saves a float and a struct TM to EEPROM and then fetches them.

// dummy = 0 statements are used to set break points to verify

// operation.

//

// Note that a byte pointer which points to the beginning of the

// quantity is passed to each function.

//

// copyright, Peter H. Anderson, Baltimore, MD, Jan, '01

#include <16f877.h>

#device *=16 ICD=TRUE

#use delay (clock=4000000)

void save_to_eeprom(byte adr, byte *p_dat, byte num_bytes);

void read_from_eeprom(byte adr, byte *p_dat, byte num_bytes);

struct TM

{

byte hr;

byte mi;

byte se;

};

void main(void)

{

float float_1 = 1.2e-12, float_2;

struct TM t1, t2;

byte *ptr, dummy;

t1.hr = 12; t1.mi = 45; t1.se = 33;

// save the float beginning at EEPROM location 0x00

ptr = (byte *) &float_1; // ptr points to first byte of float_1

save_to_eeprom(0x00, ptr, sizeof(float));

// save the struct TM beginning at EEPROM loc 0x10

ptr = (byte *) &t1;

save_to_eeprom(0x10, ptr, sizeof(struct TM)); // save t1

// now read the float and struct TM back

ptr = (byte *) &float_2;

read_from_eeprom(0x00, ptr, sizeof(float));

dummy = 0; // used to set a breakpoint

ptr = (byte *) &t2;

read_from_eeprom(0x10, ptr, sizeof(struct TM));

dummy = 0; // used to set a breakpoint to verify program works

}

void save_to_eeprom(byte adr, byte *p_dat, byte num_bytes)

{

byte n;

for (n=0; n<num_bytes; n++)

{

WRITE_EEPROM(adr, *p_dat);

DELAY_MS(8);

++adr;

++p_dat;

}

}

void read_from_eeprom(byte adr, byte *p_dat, byte num_bytes)

{

byte n;

for (n=0; n<num_bytes; n++)

{

*p_dat = READ_EEPROM(adr);

++adr;

++p_dat;

}

}