Date   : Fri, 02 Jun 2006 22:13:42 +0100
From   : Sprow <info@...>
Subject: Two serial ports on your BBC Micro

Hi,
In many control applications (for example) just having the one serial port
can be a bit restrictive as this might be used to read from a sensor while
leaving no spare port to dial the modem.

Back in 2000 I developed a second serial port and accompanying software, but
the PCBs have long been unavailable leaving the only option to slog it out
on a piece of stripboard using the circuit diagram on my "build it" pages.

I've recently taken the opportunity to update the design, shrinking the PCB
to the same form factor as MiniB, as well as adding tracks for a 9 pin
PC-style serial connector (the pads are still available for a 5 pin DIN
too!). Following recent discussions on this mailing list the base address
was also shifted up to &FC60.

These are now available to buy to those who are interested:

1. Make the whole thing on strip board
   Download details from
     http://www.sprow.co.uk/bbc/buildit.htm
   The ROM software is free to download there.

2. Buy a PCB with preprogrammed 1MHz bus logic  
   Details at
     http://www.sprow.co.uk/bbc/extraserial.htm
   The ROM is linked from there too.

3. Buy a finished PCB and just plug it in
   Details at
     http://www.sprow.co.uk/bbc/extraserial.htm
   The ROM is linked from there too.

I hope this is of interest,
Sprow.