6502 BASIC or Assembler and Intel 8271/WDC 1770 info req'd

From: Pete Turnbull <pete_at_dunnington.u-net.com>
Date: Sun Oct 7 19:57:01 2001

On Oct 7, 22:36, Philip Pemberton wrote:
> On 7 Oct 2001 1:36:56 +0100 "Iggy Drougge" <optimus_at_canit.se> said:

> > Tony mentioned teletext chips a few days ago. Don't know if those
perhaps
> are
> > only 8-colour, though. Tony?

The SAA5050 is certainly only 8-colour (plus attributes like flashing) and
as far as I know so are later teletext chips.

> I've got an SAA5050. Anyone know how to use it without the SAA5020 timing
> generator?

Take a look at the circuit diagram for a BBC micro; it uses a 6845 for
timing and an SAA5050 to generate the teletext screen mode.

http://bbc.nvg.org/mirror/www.acorn.com/ftp/documents/circuits/

> I've also got a Microvitec Cub 653 monitor. TTL input, composite sync.
How
> can I get Csync from Vsync and Hsync?

XOR them together; feed the unbuffered TTL outputs to a 74LS86 or similar,
and buffer the output with a transistor.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York
Received on Sun Oct 07 2001 - 19:57:01 BST

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