[PATCH 2/2] bmp085: Add interface documentation and link to datasheet.
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From: Christoph Mair on 26 Jun 2010 08:20 Signed-off-by: Christoph Mair <christoph.mair(a)gmail.com> --- drivers/misc/bmp085.c | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c index 16a2b2c..67ed8b2 100644 --- a/drivers/misc/bmp085.c +++ b/drivers/misc/bmp085.c @@ -1,5 +1,32 @@ /* Copyright (c) 2010 Christoph Mair <christoph.mair(a)gmail.com> + This driver supports the bmp085 digital barometric pressure + and temperature sensor from Bosch Sensortec. The datasheet + is avaliable from their website: + http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.pdf + + A pressure measurement is issued by reading from pressure0_input. + The return value ranges from 30000 to 110000 pascal with a resulution + of 1 pascal (0.01 millibar) which enables measurements from 9000m above + to 500m below sea level. + + The temperature can be read from temp0_input. Values range from + -400 to 850 representing the ambient temperature in degree celsius + multiplied by 10.The resolution is 0.1 celsius. + + Because ambient pressure is temperature dependent, a temperature + measurement will be executed automatically even if the user is reading + from pressure0_input. This happens if the last temperature measurement + has been executed more then one second ago. + + To decrease RMS noise from pressure measurements, the bmp085 can + autonomously calculate the average of up to eight samples. This is + set up by writing to the oversampling sysfs file. Accepted values + are 0, 1, 2 and 3. 2^x when x is the value written to this file + specifies the number of samples used to calculate the ambient pressure. + RMS noise is specified with six pascal (without averaging) and decreases + down to 3 pascal when using an oversampling setting of 3. + This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |