[Coco] 68/63-09 Piggy Back

[Joel Rees]

If I were going to go to the trouble to do that, I think I'd go ahead and
pull the 6809, and wirewrap a perf with headers to solder into the
mainboard, both CPUs socketed, and appropriate dipswitches to select. Maybe
even work out a hotswitch.

Might even go along with a front panel interface mod.

2017/11/01 1:44 "Tim Fadden" <t.fadden at cox.net>:

I was looking for some other info in my coco files and ran across this. I
remember someone asking about it, so here goes.  I haven't personally tried
it, but see no reason it shouldn't work.

You can stack a 6309 on top of your computer's existing 6809. Here's how...

Cut pin 39 (TSC) of the 6809, leaving a small piece sticking out of the
processor so you can solder to it.

Take a 40 pin IC socket. Cut off pins 5, 6, 33, 36, and 38. Bend out pin 39
so you can solder to it.

Stack the 40-pin IC socket on top of the 6809. Solder all of the
corresponding pins together. DO NOT solder the pins 39 together.

Now you have two options:

1.    Solder a wire from 6809 pin 39 to +5V, and another wire from socket
pin 39 to ground.

2.    Solder a 4.7K resistor between each pin 39 and +5V. Then take a SPDT
switch, connect the common contact to ground, and connect each end to a
separate pin 39.

In either case, finish up by plugging the 6309 into the socket. If you
picked option 1, you now have a 6309 system. If you picked option 2, your
system is now switchable between the 6809 and the 6309 (before power-up -
not while running!).


-- 
Tim Fadden
"Hey Schmidt, don't forget about the six P's.
Proper Preparation Prevents Piss-Poor Performance!"


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