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group9
Joined: 07 Dec 2006 Posts: 3
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writing and reading float to eeprom |
Posted: Wed May 02, 2007 9:07 am |
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hello
i am trying to write and read some float values to the 16f877a internal eeprom. and it does not seem to work. iread some junk values back if anyone could help that would be great.
thx
CCS PCM C Compiler, Version 3.212, 26318
#include <16F877A.h>
#fuses HS,NOWDT,NOPUT,NOPROTECT,NOBROWNOUT,NODEBUG,NOLVP,NOCPD,NOWRT
#use delay(clock=20000000)
#include<lcd.c>
#include <kbd.c>
#use fast_io(A)
float WRITE_FLOAT_EEPROM(long int ad, float data);
float READ_FLOAT_EEPROM(long int ad);
void main (void)
{
long int k,m;
float res[];
float val[10]={0.09,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9};
lcd_init();
for(m=0;m<10;m++)
{
WRITE_FLOAT_EEPROM(m,val[m]);
res[m]=READ_FLOAT_EEPROM(m);
printf(LCD_PUTC, "\fval=%1.3f\n",res[m]);
delay_ms(500);
}
}
float WRITE_FLOAT_EEPROM(long int ad, float data) {
int i;
for (i = 0; i < 4; i++)
write_eeprom(i + ad, *((int8*)&data + i) ) ;
}
float READ_FLOAT_EEPROM(long int ad) {
int i;
float data;
for (i = 0; i < 4; i++)
*((int8*)&data+ i) = read_eeprom(i + ad);
return(data);
} |
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PCM programmer
Joined: 06 Sep 2003 Posts: 21708
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Posted: Wed May 02, 2007 10:55 am |
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Quote: | I am trying to write and read some float values to the 16f877a internal
eeprom. and it does not seem to work. I read some junk values back.
#include <16F877A.h>
#fuses HS,NOWDT,NOPUT,NOPROTECT,NOBROWNOUT,NODEBUG,NOLVP,NOCPD,NOWRT
#use delay(clock=20000000)
#include
#include
#use fast_io(A)
float WRITE_FLOAT_EEPROM(long int ad, float data);
float READ_FLOAT_EEPROM(long int ad);
void main (void)
{
long int k,m;
float res[];
float val[10]={0.09,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9};
lcd_init();
for(m=0;m<10;m++)
{
WRITE_FLOAT_EEPROM(m,val[m]);
res[m]=READ_FLOAT_EEPROM(m);
printf(LCD_PUTC, "\fval=%1.3f\n",res[m]);
delay_ms(500);
}
022 kbd_getc.last_key
023 kbd_getc.col
024-025 MAIN.k
026-027 MAIN.m
028-029 MAIN.res
02A-051 MAIN.val
052 lcd_init.i
052 MAIN.@SCRATCH
053 lcd_init.@SCRATCH
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Look at your array declaration for 'res'. Look at the amount of RAM
allocated for it, as shown in the symbol table above. What will happen
when your code writes to the 'res' array ? What change should you
make to your 'res' array declaration to fix this ? |
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