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Re: [softrock40] Re: switching between several Softrocks RXTX

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  • Dave - WB6DHW
    Dave: The I2C address of the Si570 is programmed by the factory. You specify the address when you order. Would be great if we could program the I2C address
    Message 1 of 24 , Jan 29, 2011
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      Dave:
      The I2C address of the Si570 is programmed by the factory. You specify the
      address when you order. Would be great if we could program the I2C address and
      the startup freq., but have not heard of anyone figuring out how.

      Dave - WB6DHW
      <http://wb6dhw.com>

      On 1/29/2011 12:26 PM, Dave wrote:
      > ----- Original Message -----
      >>> As the I2C comm's between the AVR and Si570 can be a multi drop
      >>> bus, is it posible to re-assign the Si570's address,
      >>>
      >> The Si570's I2C address is fixed at the time of manufacture.
      >> Possible but probably not practical.
      >>
      >> 73 Alan G4ZFQ
      > Hi.
      >
      > Yes, I realise that, but I was wondering if it is "Fixed" as in forever,
      > or is it for example flashable. I can't imagine that in other
      > applications were multiple Si570's (or similar) could be used, that they
      > would all have the same I2C address. A lot of other I2C interface chips
      > (I/O port drivers etc) can have one of a selection of bus addresses,
      > selected by typicaly 2 address select pins (Hi, Lo, Float, 9 preset
      > "addresses" to chose from) and so on.
      >
      > Hmm... Looking at:-
      > http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf
      > Page 24 of 30, the I2C address can be specified at time of order, and is
      > indicated in the full part number.
      >
      > However, it's not as straightforward as that, there is a 6 digit code,
      > that is used to specify the factory start up frequency, and the bus
      > address. You have to request them if you want something other than the
      > default. It's not shown in plain view.
      >
      > Interestingly, these things have a Non volatile RAM internally, guess
      > it's stored in there, but not (directly) get-at-able without proprietary
      > info and kit no doubt.
      >
      > So, if one was to build something with two or more of these things, you
      > "Could" have different I2C bus address's for each device, but you need to
      > specify that when you buy the things.
      >
      > Of course... If you were to have a separate I2C digital IO chip on the
      > bus, and one of the bus multiplexers, similar to that used in the mixer,
      > you could route the I2C lines from the AVR to either of two (or more)
      > Si570's that have the same bus address. Messy, but doable, if you had
      > to.
      >
      > Interesting general I2C bus info here:-
      > http://www.bjrowa.com/download/guide.pdf
      >
      > Cheers. Back to tidying up my source code.
      >
      > Dave G0WBX.
      >
      >
      >
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