6 Mar
2012
6 Mar
'12
10:12 p.m.
If you spend a bit of time with a data sheet you would find that the 8755
programs much like the 2716 and in many cases (dataIO) it was a
trivial adapter.
Programming is simple:
For each address DO;
Present address to AD0-7 and A8-10 and cycle ALE (low, high, low):
Present data of AD0-7:
Pull prog/CE1* to 5V (NMOS high):
pulse Vdd from 5V to 25V and back to 5V, the width of this pulse
is 50mS:
Remove data:
Until done
My first programmer for that part litterally was 10 switches (address/data),
and ALE pulse button (debounced buton) and a program button
(fired the Vdd and program pulse). The circuits were pretty trivial.
I would later modify a PrommerII to do that.
Allison
On 03/06/2012 12:36 AM, dwight elvey wrote:
Hi
Is it a 8755 or a 8755A.
They program differently.
Someplace in one of the Intel books there
is programming instructions.
It didn't program like a 2716 if that is what
your asking.
Still one could wire wrap something that would
work, using the printer port of a PC.
Dwight
Date: Mon, 5 Mar 2012 22:53:15 -0600
Subject: programmer for 8755
From: kfergason at gmail.com
To: cctalk at classiccmp.org
Can anyone point me to a reasonably priced programmer for the 8755?
Lots of programmers but none seem to program this chip.
The one I have found is pretty expensive, as in out of my range ( a
couple of Elnec at $1k and more).
Was the 8755 that different?
Thanks in advance,
Kelly