help colorpal sensor

Comments

• Franklin Posts: 4,747

  2010-03-13 19:33 edited 2010-03-13 19:33

  Read this to start. www.parallax.com/Portals/0/Downloads/docs/prod/sens/28380ColorPAL.pdf
  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  - Stephen
• solvognen Posts: 3

  2010-03-13 19:56 edited 2010-03-13 19:56

  I couldn't any information except basic stamp. how can I communicate AT89C52 with colorpal? thanks...
• Phil Pilgrim (PhiPi) Posts: 23,514

  2010-03-13 20:22 edited 2010-03-13 20:22

  Some things to consider:
  
  1. The ColorPAL uses a single serial I/O line with an open-drain protocol at a baudrate between 2400 and 7200 baud.
  
  2. The AT89C52 has a full-duplex UART with separate TxD and RxD pins.
  
  3. If you want to use the 'C52's UART instead of bit-banging the serial I/O on a single pin, you can use the following circuit:
  
  
  
  4. Anything transmitted by the UART with the above circuit will also be received by it and must be discarded, unless you can disable the receiver during transmission.
  
  5. I've never used the AT89C52, so this is about all the help I can offer on that side of the cable.
  
  Good luck with your project! I know you'll get it to work.
  
  -Phil
  
  _

  

  

  share_txd_rxd.gif

  460 x 206 - 2K

  share_txd_rxd.gif 1.7K
• solvognen Posts: 3

  2010-03-13 21:44 edited 2010-03-13 21:44

  thank you for your comments but we still have got no result.
  when we are sending caracters what protocol should we use? what are the start and stop bits? thanks...
• Phil Pilgrim (PhiPi) Posts: 23,514

  2010-03-13 22:01 edited 2010-03-13 22:01

  One start bit; eight data bits; one or two stop bits; 2400 to 7200 baud; positive logic (i.e. mark is high; start bit is low). Before sending any serial data, though, you need to do a reset to get into command mode. The comments in the PBASIC program on page 5 of the doc show how to do this. You should be able to emulate the same sequence with your micro.
  
  -Phil
• kinezaras21 Posts: 4

  2010-03-19 08:53 edited 2010-03-19 08:53

  I want a help to turn the color pal. The language used is C.
• Mike Green Posts: 23,101

  2010-03-19 13:06 edited 2010-03-19 13:06

  kinezaras21,
  Please do not "cross post". It is against forum rules. If you are not getting the answers you would like in one message thread or forum, do not ask the same question in a different thread or forum. You will not get a better answer or a faster answer. The rules for these forums can be found in the "Announcements" area under "Forum Guidelines".
• crsa Posts: 2

  2011-03-12 13:29 edited 2011-03-12 13:29

  So, its possible do a comunication just whit this circuit?