 |
 |
| View previous topic :: View next topic |
| Author |
Message |
akokyaw
Joined: 11 Feb 2005
Posts: 24
|
| Please check my eeprom read program |
 Posted: Wed Oct 05, 2005 9:50 am |
 |
|
Hello,
I have some proble with reading eeprom (24C04). Please check my codes as follow and make suggestion.
| Code: |
#include <16F877.h>
#fuses XT,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
#include <2404.c>
#define size 255
void main() {
int buf,i;
long int add;
init_ext_eeprom();
add=0;
i=0;
delay_ms(250); delay_ms(250); delay_ms(250); delay_ms(250);
while(1) {
for(add=0; add<size; add++) {
buf=read_ext_eeprom(add);
printf("\r\nReading from EEPROM... Address= %ld Value= %x",add,buf);
output_b(buf);
Delay_ms(100);
}
}
}
|
The above code is not working. Any idea? But the below code is working and I really do not know why?  Please check it out. The only difference is using "Delay_S(1);" function and four "delay_ms(250);" built-in function. Compiler is 3.227.
| Code: |
#include <16F877.h>
#fuses XT,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) // Jumpers: 8 to 11, 7 to 12
#include <2404.c>
#define size 255
void Delay_S(int delay) {
int i1;
for(i1=0; i1<delay; i1++){ delay_ms(250); delay_ms(250); delay_ms(250); delay_ms(250);}
}
void main() {
int buf,i;
long int add;
init_ext_eeprom();
add=0x00;
i=0x00;
Delay_S(1);
while(1) {
add=0x00;
while(add<size) {
buf=read_ext_eeprom(add); // the memory and show it on leds,it shoaled be the same like the address
printf("\r\nReading from EEPROM... Address= %ld Value= %x",add,buf);
output_b(buf);
Delay_ms(100);
add++;
}
}
}
|
Thanks,
Ako |
|
 |
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Wed Oct 05, 2005 2:15 pm |
|
|
There's no reason for a delay to be required, normally.
My guess is that you have a very slow rise time on your power supply.
I assume your Vdd voltage is +5 volts.
Try adding the two fuse settings shown in bold, below:
#fuses XT,NOWDT,NOPROTECT, BROWNOUT, PUT, NOLVP
Those settings will make the startup be more reliable if the
problem is due to a slowly rising Vdd. |
|
|
akokyaw
Joined: 11 Feb 2005
Posts: 24
|
| eeprom read program |
| Posted: Wed Oct 05, 2005 6:36 pm |
|
|
Hi PCM Programmer,
Thank for reply. My circuit operation is to read the eeprom after power up, so I put a delay for settling time. But the problem is why the circuit is working with use of "Delay_S(1);" function instead of using four "delay_ms(250)" built-in function. This may be bug but I am not sure.
Anyway, it will be the best without delay, so I will try to change the fuse setting and post the result.
Thank a lot,
Ako |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
