[Coco] Fwd: IP packets on my coco
Dave Philipsen
dave at davebiz.com
Thu Jun 9 22:13:20 EDT 2016
Very first page of the datasheet says:
Other features..... 5V I/O tolerant
And, in multiplexed mode you just need an 8-bit data path with a few
control signals. No mapping of any range into the memory map. The
8-bit interface acts as the address lines as well as the data lines; a
common way to save pins on the old CPUs/MPUs.
Dave
On 6/9/2016 9:05 PM, RETRO Innovations wrote:
> On 6/9/2016 8:48 PM, Dave Philipsen wrote:
>> What do you need the CPLD for?
> level shifting. It's the easiest way to keep parts count low and unit
> cheap.
>
> Otherwise, you need:
>
> level shifters (2)
> glue logic (looks like it has 8 bits of address, so at least enough to
> map the 256 bytes into the memory map, I assume in ROM space)
> logic to create a pseudo CART signal when writing is needed.
> logic to only enable that CART_WRITE line in certain cases.
>
>
> Jim
>
>
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