[Coco] CoCo 1 & 2 Compatibility Question...

[Bill Pierce]

Steve, software should not be an issue between the Coco 1 & 2 with the exception of software using the serial port at higher baud rates. The Coco 1 had a different chip (not sure of numbers) and would not run at faster baud rates. This was fixed in the Coco 2 as the chip was replaced with another. Hence the different versions of HDBDOS for Coco 1 and Coco 2... The Coco 2 can handle baud rates twice as fast as the Coco 1 (about). There's also different versions of NitrOS9_dw for CC 1 & 2 for this very reason.

Also, the earlier Coco 1s had a problem with one of the chips (or circuit to the chip) involving the keyboard scan. I remember reading articles about problematic keys and joysticks, something about the extra load of the joystick causing certain keys to fail (especially after the Coco got hot). From what I read, that was fixed in later Coco 1s.

Another (small) issue would be the Coco 2b which had a different VDG chip that allowed true lower case, but I don't think any "commercial" software was ever written to use it, but there are 2 different version of NitrOS9 for Coco 2 & Coco 2b. The Coco 2b version utilizes the lowercase capability and will not run on a standard Coco 2.

And as everyone else mentioned, the Coco 1 had 12 volts on the cart port and the Coco 2 did not. Some carts can only be used with an MPI from Coco 2 and up.

 


Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull

 

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-----Original Message-----
From: Steve Batson <steve at batsonphotography.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Mon, Jun 8, 2015 9:02 pm
Subject: [Coco] CoCo 1 & 2 Compatibility Question...


I posted this on the CoCo Facebook Page as well.

Here's a question I think I
already know the answer too, but I'll ask it anyway. Was there any hardware or
software compatibility between the CoCo 1 and 2? I'm pretty sure the answer is
no. If there is, It's probably insignificant. Either way, I'm just curious if
there is, what it would be.




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