Member #132025

Member Since: April 30, 2010

Country: United States

  • Product SEN-10121 | about 2 years ago

    I have this module talking to an NXP LPC1343 at up to 1600 samples per second. You need the I2C bus running at 400kHz to achieve this sort of sampling rate. I suspect your issue is the Arduino Wire library. For some reason this sets the clock rate to 100kHz. See the following forum post for how to change http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1241668644.

    My code also reads all 6 byte blocks from each of the sensors in a single I2C transaction. This is much quicker than 6 I2C calls which is what some of the code I have seen does.

    You might also have some issue with serial baud rates. I had to push up to 500000 baud to get enough bandwidth to push all data to the PC.

    A CRO is really helping in tracking down what is happening here. Set a digital output at the start of the sensor read routine and clear it at the end. You can then tune the I2C settings to get this to the correct rate.

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