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I2C Timer Thingy? SDA\SCL — Parallax Forums

I2C Timer Thingy? SDA\SCL

GICU812GICU812 Posts: 289
edited 2008-09-10 07:10 in General Discussion
Ive got this board, it had gotten wet and the CR3032 battery in the timer was dead when I got it. I cant get it to accept programming, its not writing it to the Serial EEPROM, im not sure if the external timer is neccessary for it to work or not, but im pretty sure there is a problem in the timer regardless.

With a scope on the SCL and SDA lines, with power off to the board (battery in) I get nothing.
When I power the board I get exactly·3.4 volts, no oscillation, no movement. VCC is 3.3 volts, thats a little odd.

I dont know anything about IC2, but im assuming this is supposed to be some kind of timer.

Where should I start? I have checked the crystal, it is oscillating.


http://myfiero.com/uploads/13808_.jpg

Post Edited (GICU812) : 9/10/2008 4:13:19 AM GMT
timerschem.JPG
851 x 466 - 44K

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-09-10 04:41
    As usual, start with the datasheet. A simple Google search for the part number in your schematic came up with www.nxp.com/acrobat_download/datasheets/PCF8583_5.pdf.
  • GICU812GICU812 Posts: 289
    edited 2008-09-10 04:51
    Sorry, guess I worded that wrong,

    Should I be getting an output on the lines, or is this more of a slave device I have to signal to get it to talk?

    I was thinking at first that it should be outputting a clocking signal, but the more I think about it, maybe thats the case.
  • GICU812GICU812 Posts: 289
    edited 2008-09-10 04:55
    Yea reading the datasheet, I guess that is the case, its a slave device that must be signalled before it will output. Thought I had found a problem there...

    Anyone with more information on IC2 it would be appreciated.
  • Mike GreenMike Green Posts: 23,101
    edited 2008-09-10 05:27
    It's an I2C device and you have to use some kind of I2C driver. If you're using a Stamp, there are I2C routines described in one of the Nuts and Volts Columns (#115?). If you're using a BS2p/pe/px, there are I2C routines built into the Stamp as statements. If you're using a Propeller, there are several different I2C drivers in the Propeller Object Exchange.

    The datasheet describes how to talk to the IC (I assume you mean IC2 is U6. If not, you need to explain better what you've got and what you're trying to do).
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2008-09-10 07:10
    As mentioned above, using this alone won't do anything. Changing the battery did likely fix the problem of it not operating. But, to reach the outside world you need a BasicStamp, an SX-Protoboard, or a Propeller Protoboard.

    In sum, this is an outboard clock module that requires a microcontroller as its master.

    Wikipedia for I2C will provide you with an introductory summary. Also, the BasicStamp Manual has a very good presentation of how to use I2C.

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