Hi, I have a project where I need to write some constant values into eeprom of a 16f84a. I am writing the code in mplab and testing it on its simulator. This code won't work because simulator shows no change in eeprom values or the registers EECON1 and EECON2. It does show EEDATA and EEADR changin. Here is the simplified code. Thanks for any help. #include p16f84a.inc list p=16f84a org 0x00 ;initialize EEPROM banksel EEDATA movlw 0x34 movwf EEDATA movlw 0x01 movwf EEADR bsf STATUS, RP0 ; BANK 1 bcf INTCON, GIE bsf EECON1, WREN ; Enable Write movlw 0x55 movwf EECON2 ; Write 55h movlw 0xAA movwf EECON2 ; Write AAh bsf EECON1,WR ; Set WR bit bsf INTCON, GIE bcf STATUS,RP0 ; BANK 0 end -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist