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Monday, April 1, 2013

MoBo Audio and Header connectors

S/PDIF Header
Signal Name
S/PDIF out
Key (no pin)
the 2 pin connector plugs into your card
the other end usually has two split connectors, the black one (labeled BK) goes into the GND (ground) pin. The other one is sometimes orange (OG) and goes into your SPDIF labeled pin, most likely your positive pin but check your mobo manual.
The SPDIF input will be in the form of a 2-pin header - usually located near the DVI port.
The internal SPDIF output on the mobo will also be a 2-pin header - usually located by the CD/AUX connectors. If the mobo doesn't have this, then the external co-ax connector can be looped back to the SPDIF input on the graphics card.
In both cases, the necessary cables are (usually) supplied with the graphics card - or at least they were with my MSI 8600GTS! :-D
About VGA vs component, I think the VGA is like SCART RGB, just 31khz and component is usually YPbPr so there is a difference. my dvd player won't do progressive on the RGB.
BTW, DVI can also carry analog signals so you should be sure to use digital 'lines'.!msg/alt.comp.periphs.mainboard.asus/mn8fjHeV-B0/95U-ppJSE9sJ
  RSVD reserved
Question 1:
- what ADH pins I should use for FPOUT_R/L, RET_R/L, and AUD_GND
Question 2:
- what is the proper BIOS setting for
  > "High Definition Audio", which have options [Enabled] and [Disabled]
  > "Front Panel Type", which have options [AC97] and [HD Audio]
One of the issues is that the manual defines these setting to control the AAFP connector and there is no AAFP connector on this motherboard.
There has been several questions about the pin assignments in the AAFP and ADH connecters and here is the information I found from Intel.  Please let me know if this is correct for Asus boards.
High Definition Audio Link Header (AHD, Azalia Digital Header)
        Pin     Signal Name                     Pin     Signal Name
        1       BCLK                            2       Ground
        3       RST                             4       3.3 V/1.5 V I/O
        5       SYNC                            6       Ground
        7       SDO                             8       3.3V_CORE
        9       SDI                             10      +12 V
        11      No connect                      12      Key (no pin)
        13      No connect                      14      3.3 V/1.5V STBY
        15      No connect                      16      Ground
Front Panel Audio Header (AAFP, Analog Audio Front Panel)
        Pin     Signal Name                     Pin     Signal Name
        1       [Port 1] Left channel           2       Ground
        3       [Port 1] Right channel          4       PRESENCE# (Dongle present)
        5       [Port 2] Right channel          6       [Port 1] SENSE_RETURN
        7       SENSE_SEND (Jack detection)     8       Key (no pin)
        9       [Port 2] Left channel           10      [Port 2] SENSE_RETURN
In some other Intel documents the pin 4 in HD Audio Link Header is only for 3.3 V and pins 9, 11, 13, 15 are used for SDI0, SDI1, Aud RSVD, and Aud RSVD.

I agree that with the Sonata, only five wires should be connected.
Basically, the Sonata jacks have three contacts (tip, ring, sleeve).
MIC and MIC_PWR are tip and ring on the microphone jack.
LINEOUT_L and LINEOUT_R are tip and ring on the headphone jack.
Audio_GND is a common ground for sleeve on both jacks.
That means 1,3,5, and 9 on one side are to be connected
(MIC, MIC_PWR, LINEOUT_R, LINEOUT_L). And the ground on
pin 2 is AUD_GND on the Sonata. There is no need to wire
up the return wires, because an HDAudio system (faking AC'97 header)
does not use the return signals.
(This is copied from a Sonata manual I have on disk. Don't
  connect item 6 and 7. I added signal names to the end of each line.)
1. Microphone Signal Pin: Connect the MIC connector to this pin.  MIC
2. Microphone Power: Connect the MIC-BIAS connector to this pin.  MIC_PWR
3. Ground Pin: Connect the AUD GND connector to this pin.         GND
4. Front Right Speaker Out Pin: Connect the FPOUT-R connector to this pin. LINEOUT_R
5. Front Right Speaker Out Pin: Connect the FPOUT-L connector to this pin. LINEOUT_L
6. Rear Right Speaker Out Pin: Connect the RET-R connector to this pin.
7. Rear Left Speaker Out Pin: Connect RET-L connector to this pin.
HDAudio has enough channels in the sound chip, that return
signals are not needed (to support a sound muting function
when the headphones are plugged in). HDAudio can fake the
mute function, simply by having separate sound channels for
everything, detecting when headphones have been plugged in,
and then muting the green connector on the back of the computer.
One thing I do not understand about current HDaudio silicon, is
how the jack sensing is done. I know that some companies have
patents for audio sensing, where they measure the impedance
of the connected device. The connected device is not DC
connected, as virtually every input and output on a
sound chip is AC coupled with a small capacitor. When you look
around the sound chip, you should see a pile of small caps for
that purpose. To measure the impedance, they'd need to do
something like insert an ultrasonic signal into the jack,
and sense the current flow. Or something similar. The
exact mechanism is never detailed in the CODEC datasheets.
The Azalia standard from Intel, addresses the use of "side contact"
pairs on the jack. The jack has tip, ring, and sleeve. That
is three contacts. But, in theory, a jack can also have an
isolated pair of switch contacts, and the switch closes when
a plug is inserted in the jack. These switches are connected
to (2) four resistor trees, so that a total of eight jacks
can be sensed. The varying DC voltage value from the resistor
tree, is fed to a couple sense pins on the CODEC, digitized,
and that gives a four bit value for each tree, indicating which
jacks have plugs in them. All the complexity is necessary, so that
only a couple pins are needed on the CODEC, to detect jack
Since the vast majority of computer cases are still AC'97, they
don't have the side contacts on the jack. The last time I looked,
I wasn't even able to find the proper jack for sale to do it.
That means jack sensing is done using the proprietary or patented
method, without need for the resistor ladder or sense pins. It
means "FSENSE1" and "FSENSE2" in the above table wouldn't be
needed, and neither would there be a need for PRESENCE#, since
the header is not HDaudio.
So only five wires should be needed, just enough to get the
basic audio signals to the two jacks in question. The rest of
it seems to be covered by the CODEC, by means I don't understand.

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