Well I got a good response to my musings re British Computers.
I'm busy cutting and pasting all of the data to give me a list of who
said what and who has what. A passing thought.. should there be a
Section at Bletchley?
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org
] On Behalf Of Tony Duell
Sent: 31 August 2007 23:35
To: cctalk at classiccmp.org
Subject: Re: British Computers.
Wasn't the Dragons (Dragon 32 & Dragon 64)
made by a Welsh company?
(Still British, but I don't know anything about the computers other
than their name)
Yes. The Dragon 32 was based on the same Motorola Application Note (for
the 6883) as the Tandy Color Computer, anf is a very similar machine.
Although for some inexplicable reason, the BASIC tokens are differnntly
ordered, so a binary BASIC program from a Dragon won;t load on a CoCo
and vice versa...
The main differece between the hardware of the Dragon and the CoCo is
the printer port. There were 3 PIA lines left over once the necessary
signal had been taken for the sound, cassette port, keyboard, VDG
As er all know, the CoCo used them for a bit-banged RS232 port. On the
Dragon, they were the Strobe, Busy and ACK lines of a Centronics port.
The data for that came from the 8 keyboard scan lines (one port of a
PIA), suitably buffered. There was no problem with the dual use of this
port, the machine didn't try to read the ekybaord inptus when it was
sending a character to the printer, and the printer ignored the keyboard
scan 'data' because there was no Strobe signal along with it.
The Dragon 64 has (not surpisingly) twice as much RAM, and also a real
hardware RS23 port, based IIRC on the 6551.
Weren't the Amstrad's called Schneiders in some European country(s)?
Yes, I beleive so.