Re: Hi-speed serial interfacing from A2

[BLuRry <brendan.robert@gmail.com>]

On Jul 17, 10:57 am, Steven Hirsch <snhir...@gmail.com> wrote:
> I just _know_ there was discussion of this subject within the last year or so,
> but )&(^ Google doesn't turn up anything.  I'm interested in writing a
> filesystem driver to support an A2 as client on a DriveWire server.  This is a
> simple protocol developed for the Tandy CoCo, but it's generic enough to be
> adapted for almost any small box.
>
> The CoCo can bit-bang serial communications at 115k baud, so I'm hopeful that
> something like this is possible for some flavor of Apple 2.  There was some
> talk of folks achieving hi-speed serial I/O on bus cards (Super Serial card?),
> but cannot find the thread.
>
> Also, some years back Don Lancaster had some sort of bit-banging serial driver
> that used the game paddle connector to talk with a laser printer. Can't find
> any detail on that either, just some peripheral mention of it on the "Ask the
> Guru" website.
>
> What is the overall picture in terms of max serial rate for the various
> machines - slot-based card, //c, IIGS?
>
> Pointers to the pertinent message threads would be great.  I have the world's
> worst luck using Google for things like this.  No doubt the first person
> reading this will find it immediately and make me feel quite stupid.
>
> Steve

You can crank the SSC (super serial, //c) as well as the SCC (//gs) up
to 115200 baud.  The super serial card is not very fault-tolerant at
that speed, and I recommend using a very short cable with good
grounding/shielding.  ;-)  You have about 50 cpu cycles per byte to
send or receive a character, so it doesn't leave room for many
extras.  But it is do-able.  Both Apple Game Server and ADT Pro make
use of this mode.  (make sure you look @ the AGS v3 source in
sourceforge, not the old BerliOS site)

-Brendan