Results 1 to 10 of 10

Thread: CFAH2004A-YYH-JP and Parallel connection problems

  1. #1
    Join Date
    2006/06
    Posts
    4

    CFAH2004A-YYH-JP and Parallel connection problems

    I have a couple of CFAH2004 displays and decided to wire them up to my linux box (fedora 4). I wired them up to the parallel port and a molex by basically tying pins 2,15 to 5v and 1,3,5,16 to ground. Then the rest of the pins to the parallel port. pp16-4,pp1-6,pp2-7 etc to pp9-14. I have wired up both displays like this.

    Both displays have the same problem. When I power the computer up I get the 1st and 3rd lines turn on. All sweet. I then start LCDproc using the HD44780 driver, port 378, 8bit display. The screen flickers for a bit and then returns to the 1st and 3rd lines black. when I start the client up all that happens is the screen fades and flickers in and out in a random cycle (1-2 sec period). There is no details finer that the base 20x4 level. no char's. The only extra features is the 1/3 of lines 2,4 are activated.

    I have played with parallel port settings and lcdproc version and setting but no luck. Any ideas?

    Thanks
    Paul
    Last edited by dusty_nz; June 10, 2006 at 04:42 PM.

  2. #2
    Join Date
    2001/03
    Location
    Spokane, Washington
    Posts
    4,092
    Please take a look in this post for some good information:

    https://forum.crystalfontz.com/showt...?threadid=3257

    You need a backlight current limiting resistor. The backlight LEDs may already be damaged by connecting 15,16 directly across 5v.

    Typically you also need a potentiometer on pin 3.

    Beyond those two items, it is almost always the wiring. If you have a windows box, CFAH_WinTest may help in debugging the wiring (link in the thread mentioned above).

  3. #3
    Join Date
    2006/06
    Posts
    4

    Re: CFAH2004A-YYH-JP and Parallel connection problems

    Originally posted by dusty_nz
    I have a couple of CFAH2004 displays and decided to wire them up to my linux box (fedora 4). I wired them up to the parallel port and a mole my basically tying pins 2,15 to 5v and 1,3,5,16 to ground. Then the rest of the pins to the parallel port. pp16-4,pp1-6,pp2-7 etc to pp9-14. I have wired up both displays like this.

    Both displays have the same problem. When I power the computer up I get the 1st and 3rd lines turn on. All sweet. I then start LCDproc using the HD44780 driver, port 378, 8bit display. The screen flickers for a bit and then returns to the 1st and 3rd lines black. when I start the client up all that happens is the screen fades and flickers in and out in a random cycle (1-2 sec period). There is no details finer that the base 20x4 level. no char's. The only extra features is the 1/3 of lines 2,4 are activated.

    I have played with parallel port settings and lcdproc version and setting but no luck. Any ideas?

    Thanks
    Paul
    I have the same problem, but I tested my board and cable by that program you suggested. It works properly, but JaLCD, Smartie and other programs are dead. Need help please :-(
    I'm using 378h, 20x4 and HD44780 settings and DLportIO

  4. #4
    Join Date
    2001/03
    Location
    Spokane, Washington
    Posts
    4,092
    There is no guarantee that the other programs use the same connections as CFAH_WinTest. They may use some scheme of their own.

  5. #5
    Join Date
    2006/06
    Posts
    4
    Originally posted by CF Tech
    There is no guarantee that the other programs use the same connections as CFAH_WinTest. They may use some scheme of their own.
    The wiring is totally the same :-( Can you link me to some program which is guaranteed to work? Your Crystal Control isn't
    Last edited by Sweeteck; June 10, 2006 at 03:06 PM.

  6. #6
    Join Date
    2006/06
    Posts
    4
    Solution - sort of.

    I havn't touched my wiring yet but what I did do was plug the parallel port into my windows machine and run the LCD test tool. Woohoo, it works.

    It looks like the parallel port on my linux box is not working right. I have tested the voltages on the data pins I it looks like they are topping out at around 3.1 volts. Hard to see since it is changing all the time. Would explain what I am seeing. I did read a post somewhere about someone with a weak printer port and his solution was to put load resistors across the data pins. Have tried that but with no improvement.
    Other possibility is something on my linux config is throwing it out. Eg lpt port driver. Hmm. Will keep looking.

  7. #7
    Join Date
    2006/06
    Posts
    4
    Also the 2nd post links to a wiring schematic for a 20x4. Don't use this diagram. It is pin incomptible with the CFAH2004A. The circuit I have used is attached and works fine under windows using WinTest.
    Attached Images Attached Images

  8. #8
    Join Date
    2006/06
    Posts
    4
    You don't understand me, my schema is OK, test utility works, but only this utility. I have software problem, not hardware problem. No software works except http://www.crystalfontz.com/software...est/index.html, neither Crystal Control. If the test utility works, Crystal Control should work too, or not?

  9. #9
    Join Date
    2006/06
    Posts
    4
    Oh. sorry, missed that.

    So then you have the same issue as me. What was the wiring diagram you used? Was it similar to mine?

    Looks like I will have to do a quick install of windows to test if my problem lies with the printer port or LCDproc.

    Just had another thought. The test util installs a special lpt driver to work with the lpt port. I know with win xp that MS broke its default driver (intentionally) and I wonder if the other programs you are using are trying to go through the MS driver instead of through the alternative driver. Just an idea..

  10. #10
    Join Date
    2006/06
    Posts
    4
    Yes, that could be. I tested my LCD half a year ago and worked and afrer reinstalling Windows XP...boooom. I thing it's only system fault, because today I measured nothing on the outputs of the port when I started Crystal Control. Testing utility sends signals as expected. I'm using the same wiring as you.
    P.S. I've tested it on my girlfriend's PC too and works great
    Last edited by Sweeteck; June 13, 2006 at 03:58 AM.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •