Yep - used the X5043 in my last project. The problem you are having is caused by a silicon bug in the X5043 in that you must NOT read the status register while the write is in progress. My old code (using the X25043) always reads the status register before attempting to initiate a write in case a previous write is currently in progress. This does NOT work with the current release of the X5043. Any attempt to read the status register WHILE the write is in progress aborts the write and may also set the block write protect bits (which then need to be cleared before the next write attempt). The fix, as suggested by the Xicor FAE, was to start a 10 mS timer when the write was initiated, then check the timer before beginning another write. In my case, the timer is decremented in my background routine (1 mS ticks) and is set to NOT underflow as follows: ;TMR0 background routine decfsz EETIMR,W ;dec to min value of 1? movwf EETIMR ;nope - save new value ;rest of background routine Then, in my Write_EE routine, I replace the call to CheckWIP with: decfsz EETIMR,W goto PrevWriteNotFinished ;bail out & try later ;EEprom is ready for new write - do so movlw EE_WREN ;command for Write Enable call EEsend ;snd to eeprom - rtns with CS active bcf _EECS ;disable CS for write enable to work movlw EE_WDBL ;command for Write data in bank 0 call EEsend movfw EEADDR ;start address call EEsend movfw EEDAT0 call EEsend ;up to 15 more bytes if X5043 or 3 more bytes if X25043 ;multiple writes must NOT cross block boundaries (0000 or 00) movlw .11 movwf EETIMR ;write timer decs to 1, not 0 bcf _EECS ;initiate write ;rest of code Note - the ee write routine is part of a state machine that allows the remainder of the code to execute whether the write can occur NOW or LATER. If the write is postponed til later, the state machine keeps track of where. Hope this helps. dwayne PS - no problem getting X25043 parts so far - I was NOT told that they were discontinued, just that a part with higher endurance (the X5043) was available. Thats why I used the new part - I needed the higher endurance. dwayne >Hi, > > I don't know if you know that the X25043 was discontinued... > > But, there is a subsitute, the X5043... I received 3 samples... > > Xicor support said that this component is 100% compatible... > > I think that is not true....because my IC doesn't work more in my >circuit...My friend developted too a circuit with X25043, and we have >tested with x5043 without success too! > > Did someone have this experience too? > > Miguel Wisintainer > Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 15 years of Engineering Innovation (1984 - 1999) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. My posting messages to Usenet neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.