Weird program pak - Octal Buffers and Line Drivers

[Charles M.]

Hi everyone,

 

I recently bought an unlabeled program pak on ebay. I bought it for the cartridge case but I wanted to see what program it was. Before plugging it in, I opened the cartridge and surprise, there is no ROM inside!

It looks like some kind of prototype board with a few sn74ls244n and one sn74ls245n octal buffers. I'm new to the world of electronics (and CoCo) so I was wondering if someone on this forum ever used something similar. I want to know if it can be of any use. 

 

 

Thank you for you help,

Charles

[brain]

Someone made a "buffer" board.  the 3 '244s buffer the 16 address lines and the control lines (probably R/W, E, Q, CTS, SCS, RESET, but not CART or NMI) and the 245 buffers the 8 data lines.  You can then probe all the lines at the cart without risking damage to the CoCo itself.

 

Nice option for experimentors.

[JamesD]

There was a ribbon cable attached to that, so it probably interfaced something, but what is anyone's guess.

 

[MrDave]

Most def someone who likes to solder and experiment.. making all the address and data lines available. Could of run anything ! But probably diffrent things from time to time.

Neat

If you have a logic probe see what beepscand when !

[Charles M.]

That sounds like a pretty neat board. I don't have a logic probe yet but I'll try to interface with a microcontroller. I'm sure I can find something to do with it.

 

Thank you all for the replies! ?

 

 

[BillO]

That should be a cinch to reverse engineer and draw up the schematic.  Looks like a universal interface/bus buffer.  Not sure why there are 2 '245s as there are only 8 data lines.  However, having said that I have stopped using '244s in my projects as they are no cheaper than a '245 and a bitch to layout on a PCB.

 

Draw up the schematic and you'll get a better understanding of what it can offer.