If you can access the device using i2c protocol, it inevitably has a i2c
address as it's inner part of the procotol itself.

Cheers,
Seb

2011/4/4 Serdar K. <[email protected]>

> The thing is, i can't find any data on the datasheet of SHT21 to address
> them.
> It has an ID, and you can read the ID, but no specific I2C address, and no
> match mechanism is shown for the SHT21 ID as far as i could see.
>
>
> 2011/4/4 mattschinkel <[email protected]>
>
>> Why do you need 2 I2C ports? I2C is addressable and you may put more
>> then one device on one I2C port.
>>
>> Matt.
>>
>> On Apr 4, 3:13 am, "Serdar K." <[email protected]> wrote:
>> > 2011/3/27 mattschinkel <[email protected]>
>> >
>> > > > > MSSP2 will require a separate SPI library, or a constant in the
>> > > > > current lib to choose between 1 and 2.
>> >
>> > > > OK. I guess this is the same for serial hardware with RX1/TX2 and
>> > > RX2/TX2.
>> > > > Preprocessor to the rescue ?
>> >
>> > > Someday we all need to decide on either using the same library twice,
>> > > or create a 2nd library. A preprocessor doesn't seem like the right
>> > > solution. Again, pointers would be nice.
>> >
>> > I even do need it now.
>> > Not only to decide which module, registers, i need to use seperate ports
>> for
>> > two different
>> > devices simultaneously.
>> >
>> > My need for now is to select different two similar (better equivalent)
>> i2c
>> > devices.
>> > I use software I2C, my work is to be easier in this way, but it isn't.
>> Or i
>> > haven't enough knowledge about JAL.
>> >
>> > ..........................
>> > .....
>> >
>> > var byte I2C_PortIndex = 1
>> >
>> > .............................
>> >
>> > ---
>> >
>> //=========================================================================­=====
>> > --- //Initializes the ports for I2C interface
>> > ---
>> >
>> //=========================================================================­=====
>> > procedure i2c_initialize() is
>> > ---
>> >
>> //=========================================================================­=====
>> >
>> > if (I2C_PortIndex == 1) then
>> >   i2c_SHT21_sda_direction = low;                // Set port as output
>> for
>> > configuration
>> >   i2c_SHT21_scl_direction = low;                // Set port as output
>> for
>> > configuration
>> >
>> >   i2c_SHT21_sda = low;           // Set SDA level as low for output mode
>> >   i2c_SHT21_scl = low;           // Set SCL level as low for output mode
>> >
>> >   i2c_SHT21_sda_direction = high;               // I2C-bus idle mode SDA
>> > released (input)
>> >   i2c_SHT21_scl_direction = high;               // I2C-bus idle mode SCL
>> > released (input)
>> > end if
>> >
>> > if ( I2C_PortIndex == 2 )  then
>> >   i2c_SHT21_sda_direction_2 = low;                // Set port as output
>> for
>> > configuration
>> >   i2c_SHT21_scl_direction_2 = low;                // Set port as output
>> for
>> > configuration
>> >
>> >   i2c_SHT21_sda_2 = low;           // Set SDA level as low for output
>> mode
>> >   i2c_SHT21_scl_2 = low;           // Set SCL level as low for output
>> mode
>> >
>> >   i2c_SHT21_sda_direction_2 = high;               // I2C-bus idle mode
>> SDA
>> > released (input)
>> >   i2c_SHT21_scl_direction_2 = high;               // I2C-bus idle mode
>> SCL
>> > released (input)
>> > end if
>> >
>> > end procedure
>> >
>> > .....
>> >
>> > ....
>> >
>> > This is only the shortest procedure.
>> >
>> > This perspective is not tested OK yet, but i haven't be able to find
>> another
>> > way.
>> > And all procedures are multiplied like this by the sensor count  (and
>> also
>> > the code size is multiplied).
>> >
>> > If i could be able to dynamically change the alias to point another
>> > register, this would never be a problem.
>> >
>> >
>> >
>> >
>> >
>> > > Maybe you can ask William if you can add a optional constant for
>> > > choosing what SPI port to use (after you test with ENC28J60 of
>> > > course).
>> >
>> > > Matt.
>> >
>> > > --
>> > > You received this message because you are subscribed to the Google
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>> > > "jallib" group.
>> > > To post to this group, send email to [email protected].
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>> >
>> > --
>> > *Serdar KIZILTOPRAK
>> > Intelligence **Technology Systems
>> > [email protected]http://www.its3k.com
>> > +90(216) 518 15 00*
>> >  **- Hide quoted text -
>> >
>> > - Show quoted text -
>>
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>
>
> --
> *Serdar KIZILTOPRAK
> Intelligence **Technology Systems
> [email protected]
> http://www.its3k.com
>
> +90(216) 518 15 00
> *
>  **
>
>

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