10 Sep
2015
10 Sep
'15
11:50 a.m.
----- Original Message -----
From: "tony duell" <ard at p850ug1.demon.co.uk>
To: "General Discussion: On-Topic and Off-Topic
Posts" <cctalk at classiccmp.org>
Sent: Thursday, September 10, 2015 2:29 PM
Subject: RE: 21MX proms (per request
Your right, I didn't say that the 2716 was not a
single rail, just that it
didn't have a separate Vpp and PGM pin. It was
programmed by turning
Vpp on and off. I could be wrong that the 2732s
were that way as well.
The data sheet for the SGS-Thomson 2716 here :
http://ee-classes.usc.edu/ee459/library/datasheets/2716.pdf
says that you apply Vpp and keep it applied, set
up address and data (with G/, pin 20, more
commonly called output enable, high and E/P low)
and then program each location by taking the E/P
pin
(Pin 18, more commonly called chip enable) high
for 50ms.
That is what I remember doing. You didn't have to
pulse Vpp.
-tony
=
----- Reply -----
Yup; I still have a 2716 programmer I cobbled
together for my PET and it just has a manual DIP
switch (and LED) to turn Vpp on/off.before and
after programming. To be sure, there were
different versions but none pulsed Vpp AFAIK.
m