 |
 |
| View previous topic :: View next topic |
| Author |
Message |
albhee
Joined: 04 Jan 2014
Posts: 2
|
| How to read eeprom data. |
 Posted: Fri Sep 25, 2015 3:02 pm |
 |
|
Hi,
My CCS C compiler version is 5.008
My MCU : PIC18f2520
I am trying to save a data in the eeprom. After successfully saving the data i reprogram the chip this time for only read that data, but i am having any data only '?'. Please someone help me.
I attached the code i tried for both condition and terminal output too.
For reading and writing:
| Code: | #include <18f2520.h>
#device adc=10
#fuses HS,NOLVP,NOWDT,NOPROTECT
#use delay(crystal = 20MHz)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7, parity=N, stop=1)
#include <string.h>
void main(){
write_eeprom(0x0,0x35); // 0x35 = '5'
delay_ms(500);
printf("writing is done!\n");
unsigned int8 value=read_eeprom(0x0);
delay_ms(500);
putc(value);
while(TRUE){
}
} |
This code worked perfectly..
Result is:
But,
when i tried this code:
| Code: | void main(){
// write_eeprom(0x0,0x35);
// delay_ms(500);
// printf("writing is done!\n");
unsigned int8 value=read_eeprom(0x0);
delay_ms(500);
putc(value);
while(TRUE){
}
}
|
Now i am getting: (just a question mark!)
please someone help me.. |
|
 |
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Fri Sep 25, 2015 4:34 pm |
|
|
Do you have your programmer (Pickit 3, ICD3, CCS ICDU-64, etc.) set
to preserve eeprom ? Probably not. Your programmer is probably
erasing the eeprom when you program your PIC with the 2nd program.
Look at the settings window for your programmer. It will have a tickbox
for "Preserve eeprom on program" (which means don't erase it during
programming). Select that tickbox.
If you still have problems, then post the name of your programmer
(Pickit 2, Pickit 3, ICDU-64, or ? ). |
|
|
albhee
Joined: 04 Jan 2014
Posts: 2
|
|
| Posted: Sat Sep 26, 2015 1:59 am |
|
|
Thank you so much, PCM programmer..
i am using PICKit2. you are right, i was erasing eeprom every time i programmed the chip. |
|
|
ezflyr
Joined: 25 Oct 2010
Posts: 1019
Location: Tewksbury, MA
|
|
| Posted: Sat Sep 26, 2015 6:44 am |
|
|
Hi,
Also, 'inline' variable declarations are generally not allowed in 'C'. You can often get away with it in CCS 'C', but it's considered bad form. Declare all variables at the top of your routines.
_________________
John
If it's worth doing, it's worth doing in real hardware! |
|
|
|
|
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
