[Tinyos-help] moteIV and i2c

Joe Polastre joe.polastre at gmail.com
Fri Mar 11 19:39:32 PST 2005

Hi Anders,

  A few notes:

  1) Make sure you have a pull up resistor on the I2C SCL line,
otherwise the MCU will hang.  The MCU does not have internal pullups.

  2) I've been able to reproduce your problem but ONLY when my message
is addressed to an I2C address that doesn't exist.  When addressed to
a valid device, the problem is not there.

  I'm attaching my test program that seems to work fine with the
AD5242 i2c digital potentiometer.  If you can find out what's causing
the problem with your device, that would help track down the bug here.

  I've checked in some minor bug fixes to cvs, but none of them
address the issue you are seeing.


On Fri, 11 Mar 2005 18:09:25 +0100, Anders Blomdell
<anders.blomdell at control.lth.se> wrote:
> Hi,
> We need to use i2c on our moteIVs(revb), and if
> MSP430I2CPacket.writePacket is called with length = 1 or length = 2,
> everything works as expected, i.e if no slave acks the address
> writeDone is called indicating an error, and if a slave responds
> writeDone is called indicating success.
> But if MSP430I2CPacket.writePacket is invoked with length > 2,
> writeDone is neither called
>    1. after transmitting the slave address and no slave responds
> nor
>    2. after transmitting slave address and two bytes and then silence
> Regards
> Anders Blomdell
> _______________________________________________
> Tinyos-help mailing list
> Tinyos-help at Millennium.Berkeley.EDU
> http://mail.Millennium.Berkeley.EDU/mailman/listinfo/tinyos-help
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