13 Oct
2007
13 Oct
'07
11:20 p.m.
dwight elvey wrote:
Oh, I have built a plug-in 4201 replacement from 3 4000-series CMOS ICs, so
the equipment is functional (it's just kind of ugly - a daughter board
connected via a 16-pin DIP plug). The clock cycle used is modulo-7 so it's not
quite trivial. One might question the drive capability of the CMOS but it
seems to work well enough, I think when I did it I looked at the phases on the
'scope and they appeared as sharp as with an actual 4201.
From: dkelvey at hotmail.com---snip---
> I don't think the board in my development system used a 4201. It> seems it
just use a few transistors.
Hi
I was almost right. They used a 4 each 9602 one shots and
several transistor to create the voltages needed for the clocks.
One could use 555 directly now days instead of the 9602s.
These can output the needed voltage swing.