Reading from External Hex Address...


Closed Thread
Results 1 to 5 of 5
  1. #1
    Join Date
    Oct 2008
    Posts
    3

    Default Reading from External Hex Address...

    Hey all,

    Ive used pics on and off for a while and just recently made a TPS and AFM volt and percentage display but now im onto a new project. Im using if its adequite a 16F877A.

    I am trying to make a Nissan ECU reader using a pic similar to http://www.ecutalk.com which also uses a Pic and plugs into the Consult port of the ECU.

    I have a list of Hex addresses and the scaling so i know what address on the ECU is for what.

    Basically what im trying to do is send a HEX string to the ECU to initialise it to output (in which case its 0xff 0xff 0xef) and then read from the TX/RX port of the ECU a certain hex address, in which the ECU will send out as a byte or bytes, which the pic will then using some math will convert it to the right value to display on an LCD.

    For example: Coolant Temp from Hex address 0x08.

    How would you go about this? this is where im stumped - ill keep searching the forum but ive searched for a we while and nothing yet.


    Also, another - would an extra chip be required to read the TX/RX lines then the pic reading that chip? Max232 for example? or can i just connect straight to the chip?

    Just a note, people have made RS232 adaptors to plug in a computer to the ECU (schematics are freely available on the net), so what im trying to do is replace the computer side with a standalone unit like the one above using a 16x4 or larger LCD.

    Thanks.

    Im using PicBasic Pro 2.46 as the compiler.
    Last edited by sbouda; - 29th October 2008 at 05:20.

  2. #2
    Join Date
    May 2008
    Location
    Italy
    Posts
    825


    Did you find this post helpful? Yes | No

    Default

    You can use three push-buttons. Two for up & down to select the address you want to send out. once you have the wanted address on the LCD then you press the send button. This command SEROUT your address code and immediatly you SERIN to listen the answer that you will direct to the LCD after your maths manipulations.

    I have no idea of how many codes you need to handle, but if they are too many and will not fit in the internal eeprom, than you have the chance to use an external memory chip via I2C.

    Al.
    Last edited by aratti; - 29th October 2008 at 11:49.

  3. #3
    Join Date
    Oct 2008
    Posts
    3


    Did you find this post helpful? Yes | No

    Default

    Thanks for that - that gave me an idea on where to start and how to go about it. Ill have a crack at the SEROUT and SERIN and see what i can come up with.

    Ill be limiting the list of addresses to about 10, to the ones that i actually want and if they dont fit or i need more, I will work around some form of external memory.

    Right, ill go and see what i can do. Will post back soon.
    Last edited by sbouda; - 30th October 2008 at 03:17.

  4. #4
    skimask's Avatar
    skimask Guest


    Did you find this post helpful? Yes | No

    Default

    Do you have the specifications of Nissan's Consult protocol?
    It's not just plain 'serial' data, it's a lot more complicated than that, a lot more complicated than even ISO9141-2.

  5. #5
    Join Date
    Oct 2008
    Posts
    3


    Did you find this post helpful? Yes | No

    Default

    The only thing i could find on the protocol was this PDF which explains it. http://www.plmsdevelopments.com/imag...ds_Issue_6.pdf


    Edit: After a bit of searching, i found a few posts by oldcarguy85 about a similar thing that he has done so im looking into it.
    Last edited by sbouda; - 30th October 2008 at 07:50.

Similar Threads

  1. Instant Interrupts - Revisited
    By Darrel Taylor in forum Code Examples
    Replies: 772
    Last Post: - 17th February 2016, 22:14
  2. Can't read sequential addresses in external EEPROM
    By tjkelly in forum mel PIC BASIC Pro
    Replies: 2
    Last Post: - 18th February 2010, 14:46
  3. External EEPROM Not getting data (24LC515)
    By Tom Gonser in forum mel PIC BASIC Pro
    Replies: 3
    Last Post: - 22nd March 2005, 13:16
  4. Reading a Hex value from a Modem and showing it as Decimal..
    By Tom Gonser in forum mel PIC BASIC Pro
    Replies: 1
    Last Post: - 16th March 2005, 17:58
  5. 18f452 internal eprom help
    By TONIGALEA in forum mel PIC BASIC Pro
    Replies: 13
    Last Post: - 13th July 2004, 15:50

Members who have read this thread : 0

You do not have permission to view the list of names.

Posting Permissions

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