I2C peripheral on UBW32

Discussion in 'Embedded Systems and Microcontrollers' started by RoboticFan87, Nov 12, 2009.

  1. RoboticFan87

    Thread Starter Member

    Sep 12, 2009
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    Hey guys, If im reading from a control chip (DS2482-800) using the I2C peripheral, is there a way i can get the IO port address that that chip read from? instead of getting SDA OR SCL addresses?
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    Your question is unclear. Are you asking if there is a way way to find out what addresses the chip uses to talk to the 1-wire devices?
     
  3. RoboticFan87

    Thread Starter Member

    Sep 12, 2009
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    Yes. Ive been trying to figure that out but somehow i cant :S
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    I would start with an understanding of the 1 wire protocol. Are you sure it even uses addresses? Then I would go to the datasheet for the Maxim part.

    Hmmm...addresses, OK you mean the 48 bit unique identifiers that are programmed into each device. I don't see any way of getting that data through the DS2482-800. It may be known to the Maxim chip, but completely irrelevant to the actual operation.
     
    Last edited: Nov 12, 2009
  5. BMorse

    Senior Member

    Sep 26, 2009
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    The addresses to each chip on the I2C bus would be hardwired or programmed.... so you should know what the addresses are already..... let me look through and see what the data sheet says.... be back in a few.....

    Back again...

    Ok, it seems the device uses 7 Bit addressing, which means the least significant bit denotes weather if you are reading from it (LSB=1), or writing to it (LSB=0)

    From the example shown in the data sheet, if you took 1 DS2482-800, and wired all three An (A0,A1,A2) lines to ground those three would all equal zero (000)...

    so to write to that device the address would be b'00110000' (0x30)to read from it it would be b'00110001' (0x31)

    You can have up to eight DS2482's on each bus as slaves, so with the 7 bit addressing, you can address up to 8 differrent ones.... bit 1,2,3 correspond to A0,A1,A2. And bits 4,5,6,7 are hardwired internally to 0011.





    My .02
     
    Last edited: Nov 12, 2009
  6. RoboticFan87

    Thread Starter Member

    Sep 12, 2009
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    Oh ok...i read more through the datasheet now it makes sense. Im gonna try to see if the control chip and the micontroller are able to interface with each other through the I2C peripheral...hopefully it works

    Thanks alot guys
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    Correct me if I'm wrong, but I'm still not clear on which addresses were being referred to. BMorse is correct on the details of the 7 bit address used on the I2C bus, but there is also the 48 bit unique identifier used by the 1-wire device itself. Since there appears to be no mechanism for that quantity to be read by the DS2482-800 into some internal register so that it can be obtained over the I2C bus, I'm going to assume that the OP's question was answered.
     
  8. RoboticFan87

    Thread Starter Member

    Sep 12, 2009
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    Well my question was that once i connect my control chip with the ID chips using one of its 7-bit addresses. Now since my control chip is connected to my UBW32, i was wondering if i can read not the address of the control chip but rather the address that the control chip read from...in other words i like to get the address that the ID chip is connected to
     
  9. BMorse

    Senior Member

    Sep 26, 2009
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    from the way it looks in the datasheet, the 1 wire devices are connected to 1 of the 8 I/O's on the DS2482S, and to communicate with each one, you just need to access the right register for the appropriate channel in the DS2482S, and I don't see where it would use any 1 wire addressing to be able to retrieve that data....

    So as far as I can tell, the answer is, no, you can not get the 1 wire devices address through the I2C bus......

    My .02
     
  10. RoboticFan87

    Thread Starter Member

    Sep 12, 2009
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    Hey guys the UBW32 site is down for some reason i need to download the Firmware V.1.3 can anybody attach it so that i can save it here?

    Thanks
     
  11. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    Here it is.......
     
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