On Sat, 8 May 2004, Bob Axtell wrote:

> Anybody have experience with the Motorola MC145484
> Voice Codec? Winbond has the same thing under the P/N
> W8610IR.

> The problem is that I am having trouble understanding the relationship
> between the bit clock, the master clock, and the sync signal
> (that starts the transfer). I've read several explanations
> and none of them seem clear enough to me to work out a
> design.

I've worked with the Winbond part.  I agree that the datasheets aren't
at all clear, though it turns out the part is extremely trivial.
Bring frame sync high while the bit clock is low, set up or sample
data on the next eight high clocks, then bring frame sync low.  The
master clock isn't relevant to the software aspect.

I used an 18F part with the audio in a high-priority interrupt, since
you have to maintain a very precise 8 kHz on the frame sync pulse.

> What I am trying to do is to use the SPI port with SS\ in
> long sync frame mode. Seems like an obvious way to do it,
> but the examples never use that obvious approach.

I'm not sure I see how SPI would be helpful.  What would the SPI clock
be?

--
John W. Temples, III

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