[Coco] 16/32 bit 6809 derivative

[Francis Swygert]

I'm not so sure it was a "mistake" for Motorola to veer away from backwards compatibility with the 68K series. It's not like the 6809 was that popular -- the CoCo was the only mainstream machine in the US to use it in general computing, only a few overseas (Japan) used it. All of the overseas brands made a 68K computer later, and the arcade games that used a 6809. There were lots of things Motorola was able to do that backwards compatibility didn't allow, and that hampered Intel for a while -- they had to make processor upgrades more gradually. If Motorola had the user base that Intel (via MS-DOS and later Windows) had it would have been more beneficial to maintain backwards compatibility though. 

My understanding was that there was some backwards compatibility on the source code level, with just a few tweaks required to 6809 source to compile on a 68K processor. Doesn't help an end user though.  Frank Swygert
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