Contention?

hello,

i have uno smd edition , reading mma7455 tri-axial accelerometer using  i2c communication.
using same program, when plug in adafruit datalogger, 7455 doesn't communicate anymore.  test, references sd card , rtc commented out, , without datalogger plugged in.  datalogger plugged in, cannot read mode register of 7455.  when remove datalogger, can read (i.e mode, status, g level, etc). 
suspect there datalogger messin' comm, references sd , rtc commented out.  don't have schematic datalogger, don't know pin (or function) active.  uno , datalogger works other shields, bmp085 barometric sensor, etc.  suggestions/insight appreciated.

thanks,
steve

what i2c address of mma7455. conflict on datalogger?

[edit] , have tried i2c scanner , without logger connected?

pete

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