Manuel Franquelo

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10 years, 5 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, 4 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, 5 months ago.

posted by Manuel Franquelo 27 Nov 2013