This is great, Tony, thanks! I will try to find a handful of those
SAA5245 chips. I work primarily with PICs, so an I2C interface is
very handy for me. You rock.
-Dave
On August 27, Tony Duell wrote:
> I forgot to answer an earlier message asking just what the 3 chips were
> that you could use to get video output from a microcontroller system
>
> 1) An SAA5243 (for the UK/Europe -- I think the 60Hz-vertical version is
> the SAA5245) This is actually a teletext display IC for televisions, and
> is controlled via an I2C bus (2 wires). The nice feature is that the
> display memory can be read/written via the I2C bus, so it can be used as
> a general-purpose video display. Actually, this chips is probably
> discontinued, but there are more recent chips with the same features, and
> anyway the SAA5243 is easy to get either from scrap TVs (the
> Thomson/Ferguson ICC5 chassis, for example) or from TV spares places.
>
> 2) An 8K*8 static RAM, like a 6264
>
> 3) Some way of generating a 6MHz clock. A 74LS04 + a crystal, for example.
>
> You might want to put some kind of buffer chip on the outputs of the
> SAA5243 (I used a 74LS541 when I built something like this) which would
> increase the chip count to 4 chips.
>
> The I2C bus needs 2 lines from the microcontroller (clock and data). Each
> line should be capable of being driven as an open-collector output, and
> read as an input. The port lines on a PIC are fine. You don't need access
> to the microcontroller bus.
>
> You get a 40*25 text display (upper and lower case) with teletext-style
> block graphics and serial colour attributes. Not bad for 3 chips and 2
> port lines.
>
> There was an article on doing this in Datafile (HPCC (UK HP calculator
> user club) journal) in 1998/1999 (either the last issue of 1998 or the
> first issue of 1999 I think).
>
> -tony
--
Dave McGuire
Laurel, MD
Received on Sun Aug 26 2001 - 20:57:29 BST