Re: GI chip

>At 11:07 PM 5/7/97 GMT, you wrote:
>So never the one to throw anything away, (me or my friend), we still had the
>data book. Pretty worthless from a software point of view. Clay might be
>interested since all it contained was two pages of interfacing information.
>Pinouts, clock rates and duty cycles etc. It had one paragraph, and a
>picture of how it works. It is a type of LPC (does TI have a patent on the
>term LPC, since they're the only ones I've seen use that phrase). It
>contains a 12 coefficient filter that models the vocal track, you send it
>data in 16 (or maybe it was 15?) bit chunks, two writes per chunk, and these
>"data chunks" set up the filters, pitches or not voiced, noise, etc. commands.

Sure sounds like an LPC type arrangement. Sounds like the same
databook/sheet I have. No programming info, just some specs. (Oddly
enough, the best programming info on the SP-256 was in a (1986?) Radio
Shack technical cross reference... All sorts of stuff...

>You would have to have documentation of some kind to use these, and the
>algorithms for compressing voice into the 12 coefficients, are very
>involved. Still it might be fun playing with one, but then again isn't the
>Sega speech card just a fancier form of their development card? Just a
>different processor, and a bit more ROM space.

Well, if nothing else the 12 coefficient thing helps a little since we know
it's not the same as a TI LPC-10 coding. Maybe it's an LPC-12 varient.
The only thing that kinda makes me wonder is that Larry Brantingham (the
guy that designed the Speak-n-Spell chips and the whole 5100-5220-to
present TI LPC family)) was pretty certain that the SP-250 was a formant
synth. Hmmm. Well, I don't know enough about what the formant coding
would look like to guess so until someone comes up with the programming
docs I guess we'll call it a mystery. ;-)

-Clay

Clayton N. Cowgill Engineering Manager
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Received on Thu May 8 13:43:24 1997