EEPROM data showing FF after making 00.

deepakomanna · Joined: 06 Mar 2007 Posts: 92 Location: Pune,India

Dear Sir,
here i am using 16f913, MPLAB 7.5 Ver. & CCS PCM C Compiler, Version 3.249, 34534.
Also i am testing this using ICD 2.
Yesterday i cleared EEPROM data i.e FF TO 00. After this i read the device. All EEPROM locations data showing is 00.
today morning when again i programmed the SAME device without clearing EERPOM to 00.
Then again i read the device but ALL EEPROM DATA SHOWING IS FF.
So again programmed the device by adding statements for clearing EEPROM.It shows 00.After this i removed the clearing EEPROM statements from my programme And programmed 4 times now all EEPROM showing is 00.
So, can you plz tell me if again i programmed device, that time EEPROM data is also filled with FF.
_________________
Thank You,
With Best Regards,
Deepak.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

MPLAB has a setting to preserve the existing values of the data EEPROM
when you program the PIC with the ICD2.

Look in this menu in MPLAB to find the checkbox for the setting:

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

As a note:
When an (E)EPROM is cleared you have to check the datasheet for the default value. Most types do read all 'FF' and only a few types do read '0' after clearing.