Manuel Franquelo

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10 years, 11 months ago.

KL25Z board, MMA8451Q configuration?

Hello,

On the KL25Z board, which is the device configuration ( sampling rate etc.) used on the MMA8451Q library ?

Thanks!

Question relating to:

Last updated: 11 Oct 2012

I am not certain what are you asking, can you specify more? Have you seen the FRDM KL25Z with the accelerometer. It uses default i2c frequency, which is set to 100k.

http://mbed.org/handbook/mbed-FRDM-KL25Z-Examples

Regards,
0xc0170

posted by Martin Kojtal 27 Nov 2013

if you check the MMA8451Q datasheet, you see that the device can be configured regarding quite a few parameters. Among others:

  • ±2g/±4g/±8g dynamically selectable full-scale
  • Output Data Rates (ODR) from 1.56 Hz to 800 Hz
  • 14-bit and 8-bit digital output
  • I2C digital output interface (operates to 2.25 MHz with 4.7 kΩ pullup)

The documentation of the library is not telling which is the "full_scale" "output data rates" etc. that is being used. This is just what I want to know.

Thanks for your help, Manuel

posted by Manuel Franquelo 27 Nov 2013

2 Answers

Erik -
10 years, 11 months ago.

If you check the code you see that it just keeps the chips defaults (many libraries do). So from the datasheet then: The default full scale value range is 2g and the high-pass filter is disabled.The default value is 000 for a data rate of 800 Hz. (From me: That is of course only when you actually also sample it that vast via your connection). It uses also standard 14-bit accuracy.

Accepted Answer

Thanks for your clear and helpful information. However, I do believe that this information should be in the library documentation.

posted by Manuel Franquelo 01 Dec 2013
Manuel Franquelo
poster
10 years, 11 months ago.

posted by Manuel Franquelo 27 Nov 2013