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BS2p40 display problem — Parallax Forums

BS2p40 display problem

P.BodinP.Bodin Posts: 6
edited 2006-05-24 17:13 in BASIC Stamp

Hello
I have just invested in a BS2p40. I tested it with some diodes and buttons and everything worked as expected. Then I tried my new display, a Matrix Orbital LK204-25-WB-C74. I found an extremely simple instruction on hove to make it work with I2C communication. I wired it up accordingly and run the code. The startup display goes on nicely on power up but nothing else happens. Could someone help me out, please?

confused.gif·

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-05-23 21:21
    Where did you get the display from?· Are you connected to the right pins for I2C communication?· Do you have the address jumpers configured and your code matching that address?· Does the display work with the serial interface?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • P.BodinP.Bodin Posts: 6
    edited 2006-05-24 14:06
    I bought both the BS2p40 and the display from a Swedish reseller, ELFA. They recommended this display to use with Stamp processors. Pin 2 and 3 are connected to pin 0 and 1 on the Stamp, with pull up resistors. Jumpers 2 and 3 are left in place as the display was delivered. This results, as far as I understand, in address 5CH. I found some code examples and tried: I2COUT 0, $5C, [noparse][[/noparse]“Hello world”] and I2COUT 0, $5C, 0, [noparse][[/noparse]“Hello world”] and a few variants. Nothing helps. When reading about this it seems extremely simple. I therefore feel extremely stupid.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-05-24 15:28
    I think I see your problem...I checked your connections and wired it up the same...Nothing.· But then I looked in the documentation and Pin 3 of the LCD is the SDA line which would correspond to P0, not P1.· It sounds like you have the lines backwards.· You also don't need to specify an address...Try this. 
    I2COUT 0, $5A, [noparse][[/noparse]"Hello world"]

    This works if J0 is IN, J1 is OUT, J2 is IN and J3 is OUT.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • P.BodinP.Bodin Posts: 6
    edited 2006-05-24 17:13
    idea.gif
    I tried everything but nothing helped. Finally I canged to pins 8,9 instead. It worked perfectly at once. I don't understand why but I´m happy.
    Thank you for your help.
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