--- "Alan B. Pearce" <A.B.Pearce@RL.AC.UK> wrote:
> >> // Give the output bits some nice names (which I
> >> noticed you did, and then
> >> commented out)
> >>
> >> #define CS RA0          // Chip Select output
> >> #define SCLK RA1                // Serial Clock
> >> output
> >> #define SDI RA2         // Serial Data In output
> >>
> >> // Make CS high:
> >> CS = 1;
> >>
> >> // Make SCLK low
> >> SCLK = 0;
> >
> >Hehe, weird. I had exactly that code, totally
> >identical, it first, but I seemed too simple :).
> >Now, I found this in some code of Mike Pearce:
>
> perhaps I missed something in the early posts, but
> there is something
> strange about all this.

Strange in what way? It is likely that I'm doing some
pretty dumb things, since I know nearly nothing about
all this :).

>
> You are bit-banging an SPI interface, why not use
> the SPI hardware interface
> that is in the chip?

That would force me to use certain pins. I like to
have things set up as flexible as possible. If I can't
get it to work with software, I'll consider using the
SPI hardware interface.

> The other thing I wonder is how the chip is
> connected. Are you connecting
> the serial data out line from the PIC to the SDI
> line of the other chip, and
> the SDI line of the PIC to the SDO line of the other
> chip?

Yes, it's like that. The SDI in my code is the signal
that's going into the SDI on the chip. This is then
routed trough to the next chip. To set the volume, you
just send the MSB first, then the LSB and you do that
once for every chip. If I understand correctly you
need to start sending the data for the "last" chip, so
the chip that hasn't got it's SDO signal connected to
anything.

Regards, Anthony

PS: I'm not working on this all the time. I first want
to finish an amplifier I'm working on. I started
making it about 3-4 months ago and it should be
working this weekend, then I'll start making a case
for it. Once that's done, I can completely concentrate
myself on the digital preamp.

Ok, time to get working on that amplifier. Hopefully I
don't zap myself, I almost did that yesterday...

=====
Website: http://members.lycos.nl/anthonyvh


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