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Re: [SeattleRobotics] OOPic -- I2C -- PCF8574

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  • Tom Theron
    I understand you have one limiting resistor feeding the common anode of the 7-seg. This will result in difference in brightness depending how many segments
    Message 1 of 9 , May 2, 2002
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      I understand you have one limiting resistor feeding the common anode of the
      7-seg. This will result in difference in brightness depending how many
      segments you light. Rather remove the single resistor to the CA, and place a
      separate 220R in series with each LED cathode and the PCF8574 pin. You then
      get the same amount of current sink through each LED regardless how many are
      lit the same time.

      Your previous problems getting the LED's to glow is because the PCF8574 can
      sink something like 25mA per IO pin, but only sources 1mA or so, thus you
      have to do a sink configuration to get enough current through the LED.

      Your confusion about the "0" switching on the LED segment is because of just
      this same thing. In order to sink current "into" the pin, you have to make
      it low, or "0".

      Cheers
      Tom Theron
    • David VanHorn
      I d like to know if anyone can help me with an evaluation on Protel 99 SE. I m a bit leery of just trusting the sales rep, and I have to make a snap decision
      Message 2 of 9 , May 2, 2002
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        I'd like to know if anyone can help me with an evaluation on Protel 99 SE.
        I'm a bit leery of just trusting the sales rep, and I have to make a snap
        decision on new schematic and PCB tools.

        Am I going to be able to run this on both my main system and my portable?

        My main system is an Athlon 2000 with a ton of ram, running XP pro.
        My portable is a Crusoe 700 with 128M, running ME. It would be difficult,
        but possible, to change the OS.
        I have not been able to run the protel demo on the portable.


        Also, I need to know how well it integrates to Pro-E in the sense that our
        mechanical and plastics guys have to give me oddly shaped boards, with
        physical restrictions, and I need Protel to express those limitations to me
        in some rational and easy to deal with manner.

        Finally, any comments on ease of use, problems, gotchas etc would be most
        helpful.
        What I'm using at the moment is Orcad 386 (The dos version)

        I'm in Vancouver at the moment, and will be coming through seattle on
        friday on my way home.
      • David VanHorn
        Well, requirements are clarifying, and it s looking like I m going to orcad 9.2. Has anyone used this with pro-engineer to pass mechanicals back and forth?
        Message 3 of 9 , May 3, 2002
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          Well, requirements are clarifying, and it's looking like I'm going to orcad
          9.2.
          Has anyone used this with pro-engineer to pass mechanicals back and forth?
        • Steve Greenfield
          You could ask this on the Homebrew_PCBs list. Despite the name, there are some professionals there. We ve got over 200 members.
          Message 4 of 9 , May 4, 2002
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            You could ask this on the Homebrew_PCBs list. Despite the name,
            there are some professionals there. We've got over 200 members.

            http://groups.yahoo.com/group/Homebrew_PCBs

            Steve Greenfield
            --- David VanHorn <dvanhorn@...> wrote:
            >
            > Well, requirements are clarifying, and it's looking like I'm
            > going to orcad
            > 9.2.
            > Has anyone used this with pro-engineer to pass mechanicals back
            > and forth?


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          • Mark Pepper
            Hey I am playing with the OOPIC and the PCF 8574 on the MarkIII sensor board and I need some seed code to help point me in the right direction Has anyone got
            Message 5 of 9 , Jul 5, 2006
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              Hey

              I am playing with the OOPIC and the PCF 8574 on the MarkIII sensor
              board and I need some seed code to help point me in the right direction

              Has anyone got any code segments I could begin with please to help out.

              Regards

              Mark
            • benedict-list@hawaii.rr.com
              I finally cleaned up my motor test code. It s different from what I sent you on the OOPic list, but it s a lot easier to read now. I ve uploaded it to the
              Message 6 of 9 , Jul 7, 2006
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                I finally cleaned up my motor test code. It's different from what I sent
                you on the OOPic list, but it's a lot easier to read now. I've uploaded
                it to the Files area of the Mark III list in the OOPic example code area.
                There's a folder in there now for sensor board code, and the motor code's
                in there, too.

                I'm going to go ahead and add digital I/O stuff for the Handyboard I/O
                block and for the buzzer, but there's not really much to using them...
                it's normal OOPic I/O port code.

                Tom

                On Wed, 5 Jul 2006, Mark Pepper wrote:

                > Hey
                >
                > I am playing with the OOPIC and the PCF 8574 on the MarkIII sensor
                > board and I need some seed code to help point me in the right direction
                >
                > Has anyone got any code segments I could begin with please to help out.
                >
                > Regards
                >
                > Mark
                >
                >
                >
                >
                >
                >
                > Visit the SRS Website at http://www.seattlerobotics.org
                > Yahoo! Groups Links
                >
                >
                >
                >
                >
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