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rajenkins
Joined: 02 Dec 2003
Posts: 6
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| 12F675 eeprom write problems |
 Posted: Mon Feb 02, 2004 4:19 am |
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Hi,
I'm trying to write a measured calibration value to the 12f675 eeprom during program run.
(Working with MPLab 6.40 & PCM3.184)
I've tried write_eeprom(), the eeprom data is unchanged.
Tracing up to it using ICD2 debug shows the correct address & data values being used & the 'write' code looks fine when compared to the data sheet, but no actual write.
I've also tried Mark Hahn's code from another post on here
http://www.ccsinfo.com/forum/viewtopic.php?t=3694&highlight=12f675+eeprom
but with the present version of the compiler it does not produce workable code (the 0x55 / 0xAA section has other instructions in it, regardless of #opt level).
The write routine is only called once 'on demand', triggered by a switch input & timer sequence.
(I have tried the code stand-alone in a normal 12f675 in case the ICD was causing timing problems, but it still does'nt write).
Any ideas appreciated!
_________________
Robert Jenkins
Worksop, UK. |
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Ttelmah
Guest
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| Re: 12F675 eeprom write problems |
| Posted: Mon Feb 02, 2004 9:06 am |
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| rajenkins wrote: | Hi,
I'm trying to write a measured calibration value to the 12f675 eeprom during program run.
(Working with MPLab 6.40 & PCM3.184)
I've tried write_eeprom(), the eeprom data is unchanged.
Tracing up to it using ICD2 debug shows the correct address & data values being used & the 'write' code looks fine when compared to the data sheet, but no actual write.
I've also tried Mark Hahn's code from another post on here
http://www.ccsinfo.com/forum/viewtopic.php?t=3694&highlight=12f675+eeprom
but with the present version of the compiler it does not produce workable code (the 0x55 / 0xAA section has other instructions in it, regardless of #opt level).
The write routine is only called once 'on demand', triggered by a switch input & timer sequence.
(I have tried the code stand-alone in a normal 12f675 in case the ICD was causing timing problems, but it still does'nt write).
Any ideas appreciated! |
I am using the EEPROM read/write on these chips, with no problems. Could you post an example of the code, so we have a chance to see what is (or is not) happening!.
I am using:
| Code: |
//Routine to get a block of data from the EEPROM
void get_eeprom_block(int8 *locn,int8 nbytes,int8 address) {
int8 count;
for (count=0;count<nbytes;count++) {
*(locn++)=READ_EEPROM(address++);
}
}
//Routine to write a block of data to the EEPROM
void put_eeprom_block(int8 *locn,int8 nbytes,int8 address) {
int8 count;
for (count=0;count<nbytes;count++) {
WRITE_EEPROM(address++,*(locn++));
}
}
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Which I call with the address of the variables to read/write, the number of bytes to transfer, and the address in the EEPROM to be used.
One comment, perhaps try with an older compiler?. Just occasionally, 'oddities' appear on latter releases. Maybe this is one...
The other obvious thing, is that if the write protect bit had been set for the data_eeprom, it'd behave like this. Make sure you have NOCPD selected in your fuses, and do a full erase of the chip before programming.
Best Wishes |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Posted: Mon Feb 02, 2004 3:32 pm |
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| When working with the ICD2 you must read the eeprom from MPLAB to see the data. It does NOT update when you stop or single step. You can go to the program tab on the ICD2 settings and choose only to read the eeprom to speed up debugging. However, remember to reselect the program space when you need to download again. |
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