Newsgroups: comp.sys.transputer
From: ma@sundance.sundance.com (Mark Ainsworth)
Reply-To: ma@sundance.com
Subject: Re: Adding Serial ports to a T800
Organization: Sundance Multiprocessor Technology Ltd.
Date: Fri, 9 Sep 1994 13:57:25 +0000
Message-ID: <779119045snz@sundance.sundance.com>

In article <frank-0809941609450001@kosh.astro.ucla.edu>
           frank@bnkl01astro.ucla.edu "Frank Henriquez" writes:

> 
> Hello:
>   I'm trying to add a couple of serial ports to an existing in-house
> design, based on a T800. I'd like to use a single chip dual port DUART,
> like the MC68861 (or the equivalent Signetics part - SCN2681) or the
> Z8530, but the bus transaction times for these devices is horrible; I
> would have to add many wait states to the T800 just to meet the access
> times of these devices.

I know, that is why we use a Z80180. It provides dual RS232 (300KBaud 
synchronous mode, 38.4KBaud asynchronous mode) You can then set up the
inter-processor interface to be pretty much how you want. If you use a
FIFO then you should get pretty good performance. If you do the interface
correctly you could get it to look like an Occam channel.
Failing that you could build in a TRAM interface and buy a link 
to serial TRAM. (would you believe it, we sell them.) 
It just depends how much effort you want to put in. 

[snip..]

> My questions:
>   1) Are there DUART chips that are fast enough to handle the transputer
> bus speeds without all the extra wait state circuitry? any examples?
>   2) is there any sample Occam code for a softweare UART?
> 
> 

I don't know.
-- 
Mark Ainsworth                                     support@sundance.com
Sundance Multiprocessor Technology Ltd.                 ma@sundance.com

