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Hi,

I just started programming for the PIC18F452 in C, but
I know nothing of C. I do know some Visual Basic and
PHP and at one time (about a year ago) I was getting
advanced in mIRC scripting (resembles PHP a bit).

However, my problem is that I've never had to do such
'low level' programming, so a lot of things that are
easy on a PC suddenly become difficult for me.

Here's my problem: I want to control audio volume with
a PGA2310 (TI/BB chip), this is done through an SDI
interface.

The volume is stored in a 16-bit row, the first byte
being the right channel volume and the next 8 bits
being the left channel volume. I store the values in a
[x][2] array, with x being the number of chips (they
can be daisy-chainned, for 5.1 audio volume control
for example) and [x][1] being right channel volume,
[x][2] being left channel volume. The MSB is send
first.

My SDI line is on pin 0 of port A. Now, to determine
wether SDI should be high or low, I shift the [x][y]
byte by k (k starting at 7, going to 0) and AND it
with 0b00000001. Then to pull the line low, I AND LATA
with 0b11111110, to pull it high, I OR LATA with
0b00000001.

Is this the best way, or can I, since I put SDI on pin
0, just say something like: TRISA = (volume[x][y] >>
k) & 0b00000001?

I'm sorry if this all looks confusing, I'm totally new
to this. This is the first project I'm designing all
by myself and I fear that I'll need a lot of help,
both for hardware and software :).

PS: My pga.h file is attached. I'm sure it's full of
mistakes, if you find the time, please correct me :).

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


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