On Sat, 12 Mar 2005 22:04:14 -0600
Timothy Folks <[EMAIL PROTECTED]> wrote:

> On Saturday 12 March 2005 09:50 pm, Tyler Trafford wrote:
> > Okay, I finally went and looked at 'd'.  Is the only thing you changed
> > the audio standard?
> 
> Yes.
> 
> > You didn't touch the CX25840_SET_PATH1_SEL_CTL ?
> 
> No, I didn't.
> 
> > In 'd' that was set to 0, but is now set to 0 only for cards that
> > aren't NTSC.  (It's 2 for NTSC now.  I get no sound on anything else.)
> 
> I just now patched version i to set CX25840_SET_PATH1_SEL_CTL = 0 and got 
> loud, medium-pitched white noise and no tuner audio at all.

I have seen tuner audio on my NTSC retail 150 version with this register set to 
both 0 and 2 depending on the settings of the audio/video standard registers.

What it is -supposed- to do according to the datasheet is switch between the 
tuner audio decoder input internal to the chip and the serial audio input which 
is used for the line input (there's an external analog to digital converter 
chip on the board).

There seems to be some interaction between the audio format select registers 
and the path select registers with the ivtv code and the hardware.  I have not 
been able to characterize it and it has acted differently between some of the 
sub-versions.

If you believe the datasheets, it should be set to 0 for the tuner and 2 for 
the line input.

I have not had time to to extensive hacking on the 0.3.2i code but now that we 
can bit-bang the registers individually while the chip is running we should be 
able to characterize this.

I also bit-banged the input select registers to see what they did and they seem 
to work as the datasheet describes.

I also agree there are several versions of this card.  For instance, my tuner 
doesn't auto-detect with ANY of the versions of ivtv.  I have to force it to 39 
with a module parameter and then it works perfectly.  Go figure.

-----

Jim Reese, WD5IYT   [EMAIL PROTECTED]


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