Date   : Fri, 10 Aug 2007 09:07:08 +0100
From   : julesrichardsonuk@... (Jules Richardson)
Subject: Emulating Econet hardware?

Jonathan Graham Harston wrote:
>> Message-ID: <Marcel-1.53-0806200156-bc8xSBG@...>
>  
> Johan Heuseveldt <johan@...> wrote:
>> OTOH there is the SJ Research design - in its MDFS - with only a
>> Z80 SIO, and lots need to be done in software. I'm not familiar with
>> that serial device, so don't know how much it can do in hardware, and
>> what's left to be done in software.
>  
> The Z80 SIO does more or less everything the 6854 does. It is
> interfaced 8-style (IORQ, WR, RD), rather than 6-style (CS, R/W).
>  
> A useful extra the Z80 SIO has is that it can match the first byte
> in the packet itself and reject the frame if it's not destined for
> me. With the 6854 the CPU has to do that.

Interesting - I'd always assumed that the SIO was more concerned with 
RS-232/423 comms and wasn't flexible enough to do much else. The chips still 
seem pretty common. Farnell still sell them, although it's not clear what the 
difference is between a SIO/0 and a SIO/2 (without downloading both PDF files 
and comparing, and I can't be bothered ;)

Maybe it's a better solution to attach one of those to a PC parallel port 
rather than a 68B54 though? Better performance and still commercially available...

cheers

Jules