26 Jan
1999
26 Jan
'99
11:07 a.m.
At 10:10 AM 1/26/99 -0800, Dwight wrote:
Thanks,
The Intel booklet I have has a 1702A programmer, and it implies it is
compatable with the 1702 with a lower duty cycle. So the 1702 _could_ work
with
the address complement step and switched Vdd, Vgg, but the 1702A requires
these.
I looked in my collection and found only 1702A's. Have been thinking about
building a programmer for when I ever build a 8008 system, but the Intel
one is fairly involved. There was a simpler one in the Feb. 1978 issue of
Popular Electronics. Sone things I prefer about the second, it used a
counter and shift register to control the timing instead of monostables.
-Dave
Dave Dameron <ddameron(a)earthlink.net> wrote:
revised
on
At 11:10 PM 1/25/99 +0000, Tony wrote:
> The 1702's had 10% of the program duty cycle of the 1702A, so took 10x
> longer to
> program. The voltages were the same. I don't know what actually was the chip,
larger output/program transistors?
-Dave
Hi Dave
The 1702A's also required that the address be complemented before
the Vdd and Vgg were brought low. The 1702's didn't seem to need
this and Vdd and Vgg were left at there low states the entire time.
This also is a problem because the programmer I have doesn't
switch Vdd and Vgg.
Dwight