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Matrix Orbital LK202-25 Display Problem — Parallax Forums

Matrix Orbital LK202-25 Display Problem

ViawindViawind Posts: 5
edited 2005-09-12 21:45 in BASIC Stamp
I purchased the MK202-25 LCD display from Parallax, supposedly set up for use with the Basic Stamp. I am using the I2C bus from a BS2p. I have 4 other devices on the bus in addition to the display. The display is connected to 5V , SCL , SCA and GND on·the 4p·'Power Connector' to the left of the Keypad connector. The other 4 I2C devices work fine until I plug in the display. When powered the display comes up with the Matrix Orbital message but a scope shows the SCL line (pin 2) is being pulled permanently low by the display - hence the bus will then not work.

Is this a faulty display ? I note the backplane has shorting lands marked TTL and I2C etc·- it is the TTL pair that is bridged. Is that the problem ? There is no mention of these in the doc on the Parallax site.

Thanks

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-09-09 23:27
    Hello,

    ·· I believe the TTL is in reference to TTL rather than RS-232 signals for the Serial I/O.· This should affect the I2C though. I will see what I can come up with though.



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jon KeinathJon Keinath Posts: 146
    edited 2005-09-10 01:44
    I have one of these displays connected to my Javelin stamp via Serial.

    I belive that it can (from Matrix Orbital) have 3 different configurations, TTL (sold by parallax), RS232, and I2C, but I could be wrong.
  • Jon KeinathJon Keinath Posts: 146
    edited 2005-09-12 01:44
    I did a little research, and It looks like all you have to do is disconnect the TTL jumps and connect the I2C ones. Take a look at the PDF www.matrixorbital.ca/manuals/LK_series/LK202-25/LK202-25_210.pdf, it explains it in detail (Page 16 of the PDF). Hope this helps.
  • Tom-Matrix OrbitalTom-Matrix Orbital Posts: 38
    edited 2005-09-12 15:34
    You will need to desolder the TTL jumpers, and solder the I2C jumpers. It is not necessary, but it will also help to solder the top RS-232 jumper. I hope this works for you.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-09-12 15:54
    Okay,

    ·· I see, it's actually on page 12 of the document.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • ViawindViawind Posts: 5
    edited 2005-09-12 18:29
    Thanks. I will change the jumpers and report results. If that is the problem it would be useful if the manual that is posted on the Parallax site contained that information.·That manual·reads as though the 4p connector marled + R T - is unconditionally I2C.
  • ViawindViawind Posts: 5
    edited 2005-09-12 19:00
    Sorry guys that did not fix the problem. I tried initally just clearing the TTL jumpers and shorting the I2C jumpers. This still gave the same symptoms. Adding a short to the RS232 jumpers in addition caused the display to not initialize.

    This is a professional project that I have to deliver in a week - 10 days. If the display can be replaced under warranty·I request cross shipping. The display was purchased from the web interface by our group secretary, Kathleen McKillen at NOAA in Boulder CO on 05 July 05 Order ID: 30860. I only put it into attempted service about a week ago after completing the prototype control board with the BS2p.

    I'd appreciate your quick decision. Thanks.
  • Tom-Matrix OrbitalTom-Matrix Orbital Posts: 38
    edited 2005-09-12 19:13
    I'm guessing you have board revision 2.2 for the LK202-25?

    Post Edited (Tom-Matrix Orbital) : 9/12/2005 7:16:08 PM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-09-12 19:30
    Viawind,

    ·· Are you sure you're using the right connector on the display for the I2C connection?· Where are you connecting?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • ViawindViawind Posts: 5
    edited 2005-09-12 19:32
    Yes the board LK202-25 R2.2
  • ViawindViawind Posts: 5
    edited 2005-09-12 19:37
    Yes - per the Parallax version of the manual I am using the 4p connector to the left of the keyboard connector that is marked + R T -. This version of the board does hava another 4p connector on the right but the connections for it are not spelled out in the manual - it shows a DB9 in that position.
  • Tom-Matrix OrbitalTom-Matrix Orbital Posts: 38
    edited 2005-09-12 21:45
    I sent you a pm.
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