[Coco] Programmable Sound Generator Cart for CoCos

[RETRO Innovations]

On 11/25/2016 3:46 PM, Zippster wrote:
> Not really, but this is a pretty simple scheme.  The upper portion of the address to the bank in the
> memory chip is contained in the register.  And in a dual-chip setup like this, a bit to determine
> which chip.
>
> For instance, on the MC-10 board (16K banks) it goes…
>
> Register data for a banked area;
> 	- bits 0..4 = upper address of chip memory (32 values, 32*16=512)
> 	- bits 5..6 = not used
> 	- bit 7 = chip select (FLASH or SRAM)
>
> So, you can see, this scheme is limited to 128 banks when the MSB is used for a chip select,
> assuming an 8-bit register.  Sufficient here though.
>
> How does the CoCoFlash work?
The same basic idea, though there's more banks, so I had to dedicate a 
whole byte and then some to the bank register.  The register map is at:

http://www.go4retro.com/projects/cocoflash/

I also had to create a bit to allow the flash area to be written, since 
the high order address bits are not put on the address bus, as far as I 
know.  Though maybe you figured out another idea on your solution.

Jim