Re: Hybrid //c RAM card

[mdj <mdj.mdj@gmail.com>]

On May 13, 3:18 am, "sfahey" <sfa...@a2central.com.remove-poo-this>
wrote:
> Would it be possible to create a hybrid //c RAM card that was half Ultra RAM
> I (or II) and half slinky/memory expansion? The Ultra cards don't use the
> RAM expansion port so is it possible for them to co-exist?
>
> I assume they'd be their own seperate circuits.

Easy enough in theory, and they could be seperate and/or combined.

I've often wondered what signals are provided at the //c memory
expansion port. It seems logical that the signals required to drive
the ASIC on the Slinky card are there, but given that's /DEVSEL, the
data bus, A0-3, R/W, PH0-1, and power it's surprising that other uses
haven't been found for the port....

You only need 4 /DEVSEL locations to implement the Slinky, which may
mean only A0 and A1 are present on the connector, but if not ....

Of course all this assumes that Apple used the 'easy way' to implement
the IIc ram expansion, and simply re-used the circuitry on the Slinky
card and exposed the necessary signals to the port. IIRC, the //c ram
cards have the same ASIC as the slot cards actually on the card, and
not on the motherboard, which seems to make sense from a cost
perspective.

</braindump>