Just to update, it's been a frustrating, confusing, but rewarding weekend. I managed to spend an hour or so each day to work on the problem of *me* being able to write to the EEPROM in the C84. I'm saying *me* because it's obvious that it's something I am doing. Although I have learned a couple of things along the way: 1. For repeated writes to EEPROM (different) addresses, I found that you have to clear EECON1. I haven't gone through and really understand what is happening, but I could not get repeated writes to EEPROM working unless I cleared EECON1. Actually, I found that unless I did this, I would get the "WRERR" Bit set after a single write (no other operations) - but that the write would take. 2. MPLAB/PICStart Plus DOES write to EEPROM when it is in "Simulator Mode". It just clears (writes all 1s) in the EEPROM. The "EEPROM Memory" of MPLAB is not written to when you Assemble in MPLAB in "Simulator Mode". 3. In MPLAB "Editor Mode", "Program Memory" is NOT written when you assemble. This means to program a C84 with both Code and EEPROM data you have to: 1. Go into "Simulator Mode" 2. Do a "Build All" 3. Program the Part (Select *Everything* in "Program/Verify") 4. Go into "Editor Mode" 5. Do a "Build All" 6. Program the Part (JUST SELECT "EEPROM" in "Program/Verify") 4. You have to be in "Editor Mode" to be able to read the EEPROM. So where am I now? I have a dummy program which does what I want my final program to do - Read, Read, Write, Write, Write, Read. Which is looking at two check Bytes for AA/55 and if they aren't there, puts them, along with a 0x80 in for the Calibration Value (I'm doing a Digital Thermometer). Now that it's working, I'm looking for differences between it and the non-working code. When I find it (hopefully tonight), I'll pass it along. Thanx to Brent for sending me the original note. Myke >Return-Path: >X-Sun-Charset: US-ASCII >Date: Wed, 31 Jul 1996 10:28:12 -0700 >Reply-To: pic microcontroller discussion list >Sender: pic microcontroller discussion list >From: Brent Miller >Subject: Re: Help With 16C84 EEPROM >To: Multiple recipients of list PICLIST >X-UIDL: 93efe59d6615913a0262e2fdec3ac7dc > >Myke: > >I had a similar problem programming and reading the EEPROM data in >a 16C84 using PICstart Plus. In response to my earlier post here, >Darrel Johansen verified that there is a problem when using Simulator >mode in MPLAB with the PICstart Plus. Here is the response that >I recieved then. I don't know what the status is regarding a fix to >the problem. > >Brent > >------ > > >Subject: Picstart Plus Data EEPROM programming > >Author: Brent Miller at Internet_Exchange Date: > >6/23/96 3:50 PM > > >I have been trying, without much success, to program the data memory > >in a 16C84 using the new Picstart Plus programmer under MPLAB. > > >EEPROM data programming is supported by the Picstart Plus, at least > >according to the menus. What I have seen is that the data that gets > >written is always 'FF', regardless of the data in the source file. > > Brent, > > We've gone through testing again on the 16C84 and you've identified a > true bug. It appears that if you are in Simulator mode, the '84 data > memory is not read/programmed in PICSTART Plus. If you go to Editor > Only mode, you can manually enter data in the EEPROM window and it > will burn/read correctly. We have found a way to get this to work > correctly. If you follow this sequence, this seems to work: > > - Select Editor Only mode > - Enable PICSTART Plus > - Select 16C84 for the PICSTART Plus > - Open your 16C84 Project and Rebuild. > - Program the 16C84. > > I'll keep you and the PICLIST posted as soon as we have fully > investigated, fixed, and re-tested. > > Thanks for the feedback. > > Darrel. > > Do you ever feel like an XT Clone caught in the Pentium Pro Zone?