🚀 go-pugleaf

A week or so ago I posted an article describing my difficulties in programming
an Intel 8742 microcontroller using JDR Microdevices' new Universal
Programmer. The problems were (1) The device would not program  (2) When
reading the EPROM array, the cells were filled with "0"'s instead of "1"'s as
is usual for a blank EPROM.

Thanks to those who responded. Rather than quote everyone, I'll outline the  
reasons below.

1. I noticed in my Intel data book that Vpp was supposed to be 12.5V, and lo
   and behold the programmer was choosing 21.0V. In addition, programming
   voltage could NOT be selected independently of chip type on the menu!
   However I was able to get around this by doctoring the data file with a
   sector editor.

2. Intel 8X4Y microcontrollers have an inverting latch between the EPROM
   array and the external data bus, hence all the "1"'s look like "0"'s.

3. The over-voltage selected by the programming software burned out my first
   8742. When I ordered a new one and programmed it at 12.5V using the
   doctored data file, it programmed on the first try.

4. I am trying to get JDR microdevices to get their software re-written, and
   to replace the first 8742 that was smoked, courtesy of their software.

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-- 
l\  /l'   _  Mike Schuster          ...!dasys1!schuster
l \/ lll/(_  Big Electric Cat       schuster@dasys1.UUCP
l    lll\(_  New York, NY USA       DELPHI,GEnie:MSCHUSTER  CIS:70346,1745