Messages in this thread | | | From | "AnilKumar, Chimata" <> | Subject | RE: [PATCH v2] lis3lv02d: Add STMicroelectronics lis331dlh digital accelerometer | Date | Wed, 22 Aug 2012 15:40:25 +0000 |
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On Wed, Aug 22, 2012 at 16:09:22, Chinmay V S wrote: > Hmmm. Interesting. As i understand LIS331DLH provides 16bit data > irrespective of the full-scale/sensitivity configuration. Hence we > could effectively map +/-2G to +/-32768(signed 16bit 2's complement). > According to the current-patch right-shifting the register values by > 4(i.e. reducing 16bit --> 12bit) will mean that we lose accuracy by > ~1mG. > > Clearly this will NOT affect use-case like display-orientation in > smart-phones, but surely medical and industrial applications WILL > benefit from the additional accuracy by utilising the entire 16-bit > resolution provided by LIS331DLH hardware. > > I went through the LIS331DLH datasheet/application-note from > http://www.st.com/internet/analog/product/218132.jsp and i'm a bit > confused from your statement about +/-2G being 12bit data. Nowhere is > it mentioned that LIS331DLH provides +/-2G|+/-4G|+/-8G as 12|13|14 bit > data respectively. Then again i might be wrong... >
Look at this application note which talks about the outdata values for 2G range (page 12/31) http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/APPLICATION_NOTE/CD00215823.pdf
Corresponding to the 4G and 8G I got the details form older patches (SHIFT_ADJ_4G and SHIFT_ADJ_8G). http://driverdev.linuxdriverproject.org/pipermail/devel/2010-November/009685.html
We can easily interpret number of bits for 4G and 8G from 2G information.
Thanks AnilKumar
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