[Coco] 68/63-09 Piggy Back

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I have seen this before but if the 6309 is 100 percent 6809 compatible, then what is the benefit of having  both?

Sent from my BlackBerry Passport Red Edition.
  Original Message
From: Joel Rees
Sent: Tuesday, October 31, 2017 6:59 PM
To: CoCoList for Color Computer Enthusiasts
Reply To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] 68/63-09 Piggy Back


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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