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U25 pinout on RL's print.

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  • emillbrandt
    I am trying to track down a stray signal that I get over the opto-couplers when I am using the serial port on H4. H4 is driven by the MAX232D at U25, but U25
    Message 1 of 3 , Nov 1, 2006
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      I am trying to track down a stray signal that I get over the
      opto-couplers when I am using the serial port on H4. H4 is driven by
      the MAX232D at U25, but U25 is no where to be found on the RL's logic
      print. The MAX232D's at U22 and U23 are there, but no U25. Do I have
      the wrong print? I grabbed this one off of the web.

      Also, do you have an etch print for the RL?

      Eric Millbrandt
    • TERN (Chon)
      Eric, There s a revised version of the RL schematics. The only difference, as far as I know, is the existence of U25. I ve gone ahead and attached that here,
      Message 2 of 3 , Nov 1, 2006
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        Eric,
         
        There's a revised version of the RL schematics.  The only difference, as far as I know, is the existence of U25.  I've gone ahead and attached that here, and will also email you a copy separately.  The website version will get updated as soon as we've updated the manual.
         
        I think the schematics will answer your question about H4, but just to summarize:
         
        - H4.3 and H4.5 are the RS232 RXD/TXD signals for the second port coming off of the dual UART at U4 (RXDB/TXDB).
         
        - H4.4 and H4.6 are RS232 signals driven by the IP1 and OP1 pins... which as you point out, also goes to opto-couplers.  The idea was that these could be used for either RS232-level flow control, or even as another timer-based, bit-banged serial port.
         
        We're not aware of any other interference between the two components...?
         
        Regards,
         
        - Chon Tang
        - TERN, Inc.
         


        From: tern@yahoogroups.com [mailto:tern@yahoogroups.com] On Behalf Of emillbrandt
        Sent: Wednesday, November 01, 2006 2:50 AM
        To: tern@yahoogroups.com
        Subject: [TERN] U25 pinout on RL's print.

        I am trying to track down a stray signal that I get over the
        opto-couplers when I am using the serial port on H4. H4 is driven by
        the MAX232D at U25, but U25 is no where to be found on the RL's logic
        print. The MAX232D's at U22 and U23 are there, but no U25. Do I have
        the wrong print? I grabbed this one off of the web.

        Also, do you have an etch print for the RL?

        Eric Millbrandt

      • emillbrandt
        Chon, Thanks! That killed two birds with one stone. I found out that the DTR signal from my printer was creating the signal on the optocouplers and now I
        Message 3 of 3 , Nov 3, 2006
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          Chon,
          Thanks! That killed two birds with one stone. I found out that
          the DTR signal from my printer was creating the signal on the
          optocouplers and now I found a way to read the DTR signal.

          Eric Millbrandt

          --- In tern@yahoogroups.com, "TERN \(Chon\)" <chon@...> wrote:
          >
          > Eric,
          >
          > There's a revised version of the RL schematics. The only
          difference, as far
          > as I know, is the existence of U25. I've gone ahead and attached
          that here,
          > and will also email you a copy separately. The website version will get
          > updated as soon as we've updated the manual.
          >
          > I think the schematics will answer your question about H4, but just to
          > summarize:
          >
          > - H4.3 and H4.5 are the RS232 RXD/TXD signals for the second port
          coming off
          > of the dual UART at U4 (RXDB/TXDB).
          >
          > - H4.4 and H4.6 are RS232 signals driven by the IP1 and OP1 pins...
          which as
          > you point out, also goes to opto-couplers. The idea was that these
          could be
          > used for either RS232-level flow control, or even as another
          timer-based,
          > bit-banged serial port.
          >
          > We're not aware of any other interference between the two components...?
          >
          > Regards,
          >
          > - Chon Tang
          > - TERN, Inc.
          >
          >
          >
          > _____
          >
          > From: tern@yahoogroups.com [mailto:tern@yahoogroups.com] On Behalf Of
          > emillbrandt
          > Sent: Wednesday, November 01, 2006 2:50 AM
          > To: tern@yahoogroups.com
          > Subject: [TERN] U25 pinout on RL's print.
          >
          >
          >
          > I am trying to track down a stray signal that I get over the
          > opto-couplers when I am using the serial port on H4. H4 is driven by
          > the MAX232D at U25, but U25 is no where to be found on the RL's logic
          > print. The MAX232D's at U22 and U23 are there, but no U25. Do I have
          > the wrong print? I grabbed this one off of the web.
          >
          > Also, do you have an etch print for the RL?
          >
          > Eric Millbrandt
          >
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