[Coco] reading the ROM on a CoCo 3

jdaggett at gate.net jdaggett at gate.net
Fri Jul 28 12:43:46 EDT 2006


Mike 

IF you are trying to do that way, then you need to write  $FFDE and also 
write $E0 to $FF9D and $00 to $FF9E. Also write to $FFD3 to insure that 
the video will point to location $0400, the low resolution video ram. 

I belive that the FC registers default to $0400 in COCO 1/2 mode. But 
writing $FFDE will insure that at least the video is in the range. 

james
On 27 Jul 2006 at 22:24, Mike Pepe wrote:

> Hi guys,
> 
> Does anyone know how to read the cartridge ROM directly on a CoCo 3?
> 
> Whenever I try, I read the RAM copy. There is no activity on the cart's 
> ROM select.
> 
> I tried setting $FF90 to $8C, thinking that would switch off the MMU and 
> go directly to the hardware, but doing reads results in nothing.
> 
> The only time I get read activity on that cart select pin is after reset.
> 
> What's the trick?
> 
> -Mike
> 
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