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Re: New Member: question about ZipIt and VoIP

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  • dcgrendel
    ... It appears that there is atleast one pin on the surrounding plug for the headphone port that is some type of input to the LPC915. This could either be a
    Message 1 of 6 , Dec 31, 2005
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      --- In zipitwireless@yahoogroups.com, Tom Collins <tom@t...> wrote:
      > There's a DAC for audio output, but is there an ADC and pins for a
      > microphone input? I looked at the spec for the stero DAC (linked on
      > the Wiki), and it's an output only device -- no microphone input.
      >
      > What's up with the extra pins around the headphone connector? I
      > couldn't find much about them on the Wiki. GPIO accessible from the
      > LPC915?

      It appears that there is atleast one pin on the surrounding plug for the
      headphone port that is some type of input to the LPC915.

      This could either be a mic input or a remote control interface.

      we might never know its intended purpose without someone decapping the
      LPC915 or offical word from aeronix.

      the DAC datasheet does say the chip has input lines, but they are not
      captured, they are simply mixed in with the output.

      i've read here before someone knew of a codec that output over i2c and
      not i2s though i'm skeptical. maybe if the SPI interface used for the
      mmc is made a bit more modular we could use a SPI codec?
    • Michael Rempel
      The inputs on the dac are just to mix analog signals from another source AFTER the dac does it s work. This is a useless feature imho. I have not found a full
      Message 2 of 6 , Jan 1, 2006
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        The inputs on the dac are just to mix analog signals from another source AFTER the dac does it's work. This is a useless feature imho.
         
        I have not found a full codec that will be pin compatiable with this beast yet. I doulbt they exist. looks like a custom soldered daughter card will be needed to get an ADC in there.
         
        Michael
        -----Original Message-----
        From: zipitwireless@yahoogroups.com [mailto:zipitwireless@yahoogroups.com]On Behalf Of dcgrendel
        Sent: Saturday, December 31, 2005 5:30 PM
        To: zipitwireless@yahoogroups.com
        Subject: [zipitwireless] Re: New Member: question about ZipIt and VoIP

        --- In zipitwireless@yahoogroups.com, Tom Collins <tom@t...> wrote:
        > There's a DAC for audio output, but is there an ADC and pins for a
        > microphone input?  I looked at the spec for the stero DAC (linked on
        > the Wiki), and it's an output only device -- no microphone input.
        >
        > What's up with the extra pins around the headphone connector?  I
        > couldn't find much about them on the Wiki.  GPIO accessible from the
        > LPC915?

        It appears that there is atleast one pin on the surrounding plug for the
        headphone port that is some type of input to the LPC915.

        This could either be a mic input or a remote control interface.

        we might never know its intended purpose without someone decapping the
        LPC915 or offical word from aeronix.

        the DAC datasheet does say the chip has input lines, but they are not
        captured, they are simply mixed in with the output.

        i've read here before someone knew of a codec that output over i2c and
        not i2s though i'm skeptical.  maybe if the SPI interface used for the
        mmc is made a bit more modular we could use a SPI codec?







      • dcgrendel
        ... Yes, I believe I said that in my last message. Maybe it just needed reiterating. ... beast ... will be ... They probably don t exist. There are 2 options
        Message 3 of 6 , Jan 3, 2006
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          --- In zipitwireless@yahoogroups.com, Michael Rempel
          <michael_rempel@s...> wrote:
          >
          > The inputs on the dac are just to mix analog signals from another source
          > AFTER the dac does it's work. This is a useless feature imho.

          Yes, I believe I said that in my last message. Maybe it just needed
          reiterating.


          > I have not found a full codec that will be pin compatiable with this
          beast
          > yet. I doulbt they exist. looks like a custom soldered daughter card
          will be
          > needed to get an ADC in there.

          They probably don't exist. There are 2 options available, replacing
          the existing dac with a full codec like the CS4270, or suplimenting it
          with such a chip and ignoring the output side of the addon.

          The question I have to ask: is the SDIN pin on the cpu connected to
          anything accessable, even a pull up/down?
          If not, then we are likely stuck hammering another GPIO, which are in very
          short supply last I recall.
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