[Coco] Color basic 1.0, 1.2 differences.

[Darren A.]

>From: Phill Harvey-Smith <afra at aurigae.demon.co.uk>
>
>Hi,
>
>I'm currently working on cleaning up and unifiying the way that memory
>in mess is handled between the CoCo 1/2 and Dragon machines. I seem to
>have this mostly sorted,however I have run into the following problem,
>that the CoCo 1 emulation using Color basic 1.0 seems only to recognise
>the 4K and 16K configurations, setting it to 32K or 64K results in a
>machine with 4K.
>
>Tracing through the initialisation code, I have found that the init
>sequence is different for CB 1.0 and CB 1.2 was the above behavior a
>limit of CB 1.0 ? that it could only support 4K and 16K of memory. If
>this is the case then I'll change the coco driver so that it can only be
>configured for these settings, if not I'll have to dig deeper :)
>
-
The initialization routine in Color Basic 1.0 did not setup the SAM for 
32K/64K mode. It only supported the 4K and 16K configurations of the early 
CoCo1 boards.  Color Basic 1.1 and 1.2 both supported 32K/64K configurations 
by detecting additional jumper settings on the later boards.  I think this 
is described in the Unravelled books.

Darren

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