🚀 go-pugleaf

A friend of a cousin of mine in Huntsville AL has designed himself a little
interface board to go on the 800XL parallel bus connector, based on
information my cousin supplied him on the pinouts of that connector.
The interface is a simple starting point for hanging gadgets on the bus and in
the process learning more about how to go about it.

My cousin has supplied me with a schematic diagram of what his friend built,
and I offered to send copies to those interested.  The schematic is in the
form of five pages, each showing a fairly simple section of the interface.
There is also a page showing the bus pin connections, and I have now added a
page of explanation of how to use the information.

The movie version will be coming out later in the year.

To make it work, you would have to understand how the sections are hooked
together and make sure that all details are worked out correctly.  For
example, if you want the serial port(s), you would need to fill in some
details on how to divide the clock signal down to the baud rate.  This means
deciding how to hook up the pins of two chips not shown on the existing
diagram.  Not a big problem, and I will try to make sure that anybody who
really wants to build one gets all the information needed.  But it is
definitely not a Heathkit type project with everything all spelled out.
If you are not experienced in digital system design there will be a few things
to learn.  You might also find more detailed information and construction
projects in some of the Atari magazines or in Ciarcia's column in BYTE.

Then there is the matter of driver software.  Once you have built the thing,
it won't DO anything unless you have a software driver to run it.  Since it is
non-standard (it isn't even on the SIO bus), somebody will have to write it.
Or I can try to get a copy of the driver my friend's cousin wrote.

I would sum up by saying that if what you want is both an interface and a
detailed understanding of how it works and how to modify and extend it, then
this is for you.  If you just want an interface and don't want to have to
think a lot to get it working, then it would be better to buy what you want.

-John Sangster
jhs@mitre-bedford.arpa