RML LINK 480Z with network connection

From: Paul Williams <celigne_at_tinyworld.co.uk>
Date: Sun Nov 12 18:04:22 2000

Tony Duell wrote:
>
> Paul Williams wrote:
> >
> > Oddly enough, the 480Z talks to the disk drive through the serial
> > port. The disk drive also contains another serial port, which I've
> > yet to experiment with.
>
> Ah, so that's how it was done. I presume it uses the SIO-4 connector
> (which is a serial port using a Z80-SIO, as opposed to SIO-2, which
> is bit-banged, and not particularly useful). I wonder what baud rate
> and protocol it uses -- it would be interesting to attempt to use
> another computer as a 'disk drive' for the 480Z (well, interesting
> for those of us who have 480Zs and no drives).

Yes, it's the SIO-4 connector. I haven't managed to get the disk drive
open yet (oh, the shame of it!) because it looks like it's been rivetted
together (or screws with the heads taken off).

I'd like to investigate the disk drive protocol too. I see if I can hack
together another cable with a flying D-type and borrow a protocol
analyser from work.

As I mentioned, there is a second serial port on the disk drive. It is
labelled "Serial I/O-4, interface for printer etc.", so the protocol
allows for pass-through to other devices. Rather nice.

> Looking at the schematics, I don't see how it can fail to produce
> a colour display on an RGB monitor.

That's good news. I've got a Microvitec Cub 653 that I use for my QL, so
I'll see if I can hook that up.

I've just spent the last couple of hours trying to decode the hi-res
graphics code. The graphics operations are very slow. I wrote a sprite
routine for it at school and I remember that the video RAM is accessed
through output ports which have got very strict timing constraints, so
the code is forever waiting for the next chance to access the RAM.

Looks like plenty to work on!

Cheers,
Paul
Received on Sun Nov 12 2000 - 18:04:22 GMT