[Coco] Programmable Sound Generator Cart for CoCos
go4retro at go4retro.com
Fri Nov 25 23:12:14 EST 2016
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:
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.
More information about the Coco