6845 CRTC, Microvitec VDU/BBC Micro sync waveforms (was Re: CoCo's *are* real...)

From: Philip Pemberton <philpem_at_dsl.pipex.com>
Date: Mon Sep 9 01:24:00 2002

Tony Duell wrote:
> Csync is a particulary nasty signal to look at on most small logic
> analysers because it's got narrow pulses that are quite widely spaced.
> I'd rather not use this unless I have to.
Fair enough.

> What do you need to know?
>
> Pulse width/frequency of Hsync and Vsync?
> Timing between leading edges of Hsync and Vsync?
> Timing between Hsync and start of video line?
All of those please.

> Of course many of those can be controlled by software on the 6845. I
> assume you just want the default values for the Beeb. Do you want me
> ot use a particular video MDOE?
MODE 7 would be OK. I need the timing info to connect a Teletext i/f up to
the Cub, so MODE 7 (Teletext emulation) would be the logical choice.

Thanks.
--
Phil.
philpem_at_dsl.pipex.com
http://www.philpem.dsl.pipex.com/
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Received on Mon Sep 09 2002 - 01:24:00 BST

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