[Coco] Solution to switch between 6809 and 6309

[Arthur Flexser]

Bill, I agree with you about there being no need to switch back and forth
between 6809 and 6309, but I'd put compatibility at more like 99.9%.  I
once did receive a Basic program that turned out not to work right on
account of my having a 6309 installed.  The author, who was not an assembly
language programmer, used an EXEC he found listed in some handy guide
somewhere.  It jumped into the middle of a ROM instruction, and worked okay
with a 6809 because the first byte executed was an illegal opcode and was
therefore ignored by the 6809 under which the program was developed.  But
when I tried the program with a 6309, the 6309 vectored the illegal opcode
to its error handler address, which hadn't been initialized, and the
program crashed.  So, no 101% compatibility, or even 100%.   But close.

Art

On Sun, Jun 14, 2015 at 3:56 PM, Bill Pierce via Coco <coco at maltedmedia.com>
wrote:

> John, why would you even want to switch back to a 6809? The 6309 is 101%
> compatible to the 6809 and even in native 6309 mode, 6809 code is still
> 100% compatible. There is no reason to switch back and forth. In RSDOS,
> unless the program turns 6309 mode on, it will stay in 6809 mode. NitrOS9
> is one of the few softwares/OS's that actually uses the 6309 native mode.
>
> Also, if you do go with the 6309, get Cloud9's "ProTector". It has
> protection circuitry to protect the CPU, and if you ever do want to pull
> the 6309 and put the 6809 back in, it's all socketed.
>
>
>
>
>
>
> Bill Pierce
> "Charlie stole the handle, and the train it won't stop going, no way to
> slow down!" - Ian Anderson - Jethro Tull
>
>
>
> My Music from the Tandy/Radio Shack Color Computer 2 & 3
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>
>
>
> -----Original Message-----
> From: John B <trymyz at gmail.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Sun, Jun 14, 2015 3:09 pm
> Subject: [Coco] Solution to switch between 6809 and 6309
>
>
> Does anyone know if there is a plug in board that would allow dual sockets
> to
> switch between the 6809 and 6309?  I have read about the piggy back
> option, but
> it seems to have mixed reviews.  Any info would be
> greatly
> appreciated.
>
> John
>
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