[Coco] Writing a virtual GPU / FPU device.

[Stephen Fischer]

third party

I believe that such a list does exist but my very well trained dog 
(Google) did not present the list I have seen before, but many other 
results for "coco memory map". If I include "coco in a Google search it
knows exactly what I want, 3-4 pages of documents all over the web that 
are very detailed about the coco memory map.

http://www.colorcomputerarchive.com/coco/Documents/Books/ColorComputerMemoryMap.pdf 
is not that list but a document that I have not seen before.

Trying to not conflict with all other devices likely is not possible.

With the ghosting due to incomplete memory address decoding and every 
hardware designer also wanting to not have any conflicts, you run into 
what I was taught in a EE class. Don't care methods to reduce the 
complexity of hardware designs that were widely used when the CoCo was 
designed, thus the ghosting.

If you are the only person to ever see your work, then a flexible method 
that allows movement should you obtain an conflicting device will work.

If others will see your work then it is a judgement call based on that 
list that someone will point you to.

SHF


On 5/22/2019 9:31 PM, Walter Zambotti wrote:
> I kind of have exposure to virtual devices via the OVCC project that allowed
> me to investigate how the dynanmic device modules are designed.
> 
>   
> 
> Now I would like to create my own GPU / FPU device.
> 
>   
> 
> I would like to know how device designers chose the memory addresses to
> where the device maps its registers.
> 
>   
> 
> Of course I don't want to conflict with any other devices!
> 
>   
> 
> Is there a list of memory addresses used by all other devices?
> 
>   
> 
> The Tandy CoCo Service manual provides all the standard device mappings but
> what about third party?
> 
>   
> 
> Walter
> 
>