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External car CD changer LCD on BS2? — Parallax Forums

External car CD changer LCD on BS2?

egereger Posts: 9
edited 2006-07-27 03:53 in BASIC Stamp
I have this old kenwood LCD module from a car CD changer. It has 9 buttons on it and the LCD is driven by a Sanyo LC75821. I found documentation for the chip here: http://www.alldatasheet.com/datasheet-pdf/pdf/40942/SANYO/LC75821E.html

It looks like the chip has 8 wires for serial communication and power (which correspond to the 8 wire cable). It works up to 6.6volts and looks like something I might be able to play with on my bsp2p24 demo board.

My question is, what should I be looking for or reading about to find out what each wire is used for, what clock speed to run, and what commands drive the device? I am not sure if there is a trial and error path I could take. But i'm hoping that it isn't impossible without the documentation. I doubt i'll be able to find any data or specs on how kenwood interfaced it with their cd changer.

Thanks for your time!

Comments

  • willthiswork89willthiswork89 Posts: 359
    edited 2006-07-26 04:33
    ive wondered this same question if i try to rip out an old LCD display if i could toss it on my bs2... lets se if anyluck
  • willthiswork89willthiswork89 Posts: 359
    edited 2006-07-26 05:18
    i have an LCD out of a 20 Q's Game... trying to use it for this but no luck
  • FranklinFranklin Posts: 4,747
    edited 2006-07-26 15:43
    Pages 3, 4 and 7 seem to apply to your question. It looks like a syncronous (sp) serial device. They have been discussed quite a bit here.

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    - Stephen
  • egereger Posts: 9
    edited 2006-07-27 02:06
    Franklin said...
    Pages 3, 4 and 7 seem to apply to your question. It looks like a syncronous (sp) serial device. They have been discussed quite a bit here.

    I would love to read more about it. What pages are you referring to? I checked those pages in the PDF manual. But they are just about the manual, part of the contents, and page 4 is blank.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-07-27 03:23
    Pages 3, 4, and 7 in your datasheet.

    ( Crikey. )


    Post Edited (PJ Allen) : 7/27/2006 3:27:35 AM GMT
  • egereger Posts: 9
    edited 2006-07-27 03:53
    I see, I understand the connection information. Though it will be difficult since there 8 wires go through many traces on the PCB and through lots of other little devices (mostly resistors looks like). But I guess I am not understanding how to work the display (what data to send to it).

    Now I have done some more tracing on the PCB and have found another controller on it which is a NEC PD6124A. The datasheet for it specifically says it is used for communication in tv's, stereos, and other household equipment (i'm guessing this is what receives the commands and tells the LC75821 what lights to turn on).

    Guess this is going to be too difficult for my knowledge...
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