EEPROM's data was lost

[Jackman]

Hi to all,
I have had some problems with my EEPROM's data. I'm using a PIC16F877A with PCW+ICD-U40. Sending a float number to a address location (using #include <internal_eeprom.c> library), I can see how the bytes are changing when I write over there in the debugger window , but when I switch off the PIC, the EEPROM is "white" again. Probably, there is a command or fuses that I'm not using well. Please, see the program below and feel free to comment it, I 'm just a beginner in C...

Thanks a lot and Saludos.

#include <16F877A.h>
#device ICD=TRUE
#fuses HS,LVP,NOWDT,NOPUT,NOPROTECT,NOWRT,DEBUG
#use delay (clock=10000000)
#include <lcd.c>
#include <math.h>
#include <internal_eeprom.c>
set_tris_e (0x0F);
////////////////////////////////////// GLOBALES //////////////////////////////////////
int address=0;
const int v_max=5.00;
const int escala=1023;
const float ctte=1.667;
const float mbar=11.33;
char s[16],i;
float voltage,expo,expo1,pressure,pressure1,value, data;
char CONST set[]="Set Level Alarms";
char CONST welcome[]=" IRWFS VACUUM ";
char CONST error[]="SensorNotConnect";

////////////////////////////////////// SUBRUTINAS ////////////////////////////////////////
void print(float press)
{
lcd_gotoxy(1,2);
sprintf(s,"Vac=%1.2Embar\n",press);
for(i=0;s[i]!='\0';i++)
{
lcd_putc(s[i]);
}
delay_ms(200);
}


float calcula_voltage(float value, float &voltage)
{
value=0;
value=read_adc();
delay_ms(100);
voltage=(((value*v_max)/escala)*2);
}

float calcula_exp(float v)
{
return (ctte*v)-mbar;
}

float calcula_pressure(float xx)
{
return pow(10,xx);
}

void not_sensor()
{
lcd_gotoxy(1,2);
for(i=0;error[i]!='\0';i++)
{
lcd_putc(error[i]);
}
output_high(PIN_A3);
delay_ms(1000);
return;
}


void alarm_enable ()
{
while(input (PIN_E1))
{
read_float_eeprom(address);
if (input (PIN_E0))
{
output_low(PIN_A3);
set_values();
}
if (data<=voltage)
{
char mess[]=" Vacuum Alarm!! ";
lcd_gotoxy(1,1);
for(i=0;mess[i]!='\0';i++)
{
lcd_putc(mess[i]);
}
print(pressure);
output_high(PIN_A3);
//restart_wdt();
delay_ms(300);
break;
//restart_wdt();
}
else
{
output_low(PIN_A3);
calcula_voltage(value,voltage);
expo=calcula_exp(voltage);
pressure=calcula_pressure(expo);
print(pressure);
}
return;
}
}

void set_values()
{

while(input (PIN_E0))
{
read_float_eeprom(address);

lcd_gotoxy(1,1);
for(i=0;set[i]!='\0';i++)
{
lcd_putc(set[i]);
}
print(pressure1);
if (input (PIN_A1))
{
data=data-0.001;
write_float_eeprom(address,data);
expo1=calcula_exp(data);
pressure1=calcula_pressure(expo1);
print(pressure1);
delay_ms(100);
}

else if (input (PIN_A2))
{
data=data+0.001;
expo1=calcula_exp(data);
pressure1=calcula_pressure(expo1);
write_float_eeprom(address,data);
print(pressure1);
delay_ms(100);
}
}
}




/////////////////////////////////////// PRINCIPAL //////////////////////////////////////

void main()
{
setup_adc_ports(AN0);
set_adc_channel(0);
delay_ms(100);
setup_adc(ADC_CLOCK_DIV_8);
lcd_init();
lcd_putc('\f');
//dato1=5.00;
//setup_wdt(WDT_2304MS);

while(TRUE)
{

//restart_wdt();
lcd_gotoxy(1,1);
for(i=0;welcome[i]!='\0';i++)
{
lcd_putc(welcome[i]);
}
calcula_voltage(value,voltage);
expo=calcula_exp(voltage);
pressure=calcula_pressure(expo);
if(voltage<1>8.60)
{
not_sensor();
}
else if(input(PIN_E1) )
{
alarm_enable();
//output_high(PIN_A3);
}
//else if(input(PIN_E0) )
//{
//output_low(PIN_A3);
//set_values();
//}
else
{
print(pressure);
output_low(PIN_A3);

}
}
}

[PCM programmer]

[vu2iti]

Hi every one,
I have the similar problem. I am using 16F877A programmed using teh hex file genrated from C compiled using pic 3.xxx.
Some times, the DATA EEProm is getting corrupted. The pic based system is in production and only in few units, this problem is noticed.
The EPPROM data is modified only once at the time of installation. After that no write operation is attempted. The corrupted chi can be reporgammed and without any problem.

Is it due to the error in the compiler ofr the is the probnlem is in the PIC chip?
Any help?
Thanks,
VU2ITI

[Ttelmah]

Have you tried PICs from anither batch?. If the problems remains, I'd say probably neither.
How is the data written 'once at the time of installation'?. If there is a write routine present, then the possibility exists that this is being erroneously called. However the most likely thing, is a voltage going over 5v on the MCLR line. This can corrupt the data anywhere on the chip, but seems to upset the EEPROM first.

Best Wishes

[Jackman]

Thanks for your reply!
Ok, by the moment, I changed the wrong fuses and the variable's format, also I try with another chip from a different batch but the problem is still there. I checked that MCL is at least 5V and it isn't going up. I'm agreed with "Ttelmah", probably there is a bug in the program or I'm calling/using a wrong routine. Be aware that i'm using a internal library called "internal_eeprom.c" to write and read the EEPROM. Thanks and let's think about it!
Saludos,

[vu2iti]