Re: Appletalk on IIC

[Eric Jacobs <no@no.no>]

John Ruschmeyer wrote:
..
> We can probably also make some assumptions. Mainly that the external box
> definately contained a Z8530 and probably contained a 65C02. (The latter
> assumption is based on the fact that both the Workstation card and the PC
> LocalTalk board had 65C02/Z8530 hardware.)
> 
> The question then becomes whether some enterprising hardware hacker could
> but the equivalent of a Workstation card in a standalone box and implement
> the //c-to-card protocol.
> 
> Anybody want to take that challenge on?
> 
> <<<John>>>

I'm very curious about what that 65C02 actually does. The SDLC protocol underlying
LocalTalk is implemented by the Z8530 (filtering incoming packets for the correct
address, etc) Probably when the 8530 detected an appropriate packet coming in, it
would signal the card's 65C02, which would begin reading the packet and deal with
the three or four different types of LocalTalk packets. (RTS, CTS, ACK, and ENQ,
if I remember correctly.) After that it would simply generate an interrupt for the
main 6502 and act like a simple FIFO for the rest of the time.

On second thought, forget about the LocalTalk. Let some enterprising hardware
hacker work on an Ethernet card for the //c!

-ej