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Diffstat (limited to 'Documentation/hwmon/ds1621')
| -rw-r--r-- | Documentation/hwmon/ds1621 | 156 |
1 files changed, 93 insertions, 63 deletions
diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621 index fa3407997795..552b37e9dd34 100644 --- a/Documentation/hwmon/ds1621 +++ b/Documentation/hwmon/ds1621 @@ -2,42 +2,61 @@ Kernel driver ds1621 ==================== Supported chips: + * Dallas Semiconductor / Maxim Integrated DS1621 + Prefix: 'ds1621' + Addresses scanned: none + Datasheet: Publicly available from www.maximintegrated.com * Dallas Semiconductor DS1625 + Prefix: 'ds1625' + Addresses scanned: none + Datasheet: Publicly available from www.datasheetarchive.com * Maxim Integrated DS1631 + Prefix: 'ds1631' + Addresses scanned: none + Datasheet: Publicly available from www.maximintegrated.com * Maxim Integrated DS1721 + Prefix: 'ds1721' + Addresses scanned: none + Datasheet: Publicly available from www.maximintegrated.com * Maxim Integrated DS1731 + Prefix: 'ds1731' + Addresses scanned: none + Datasheet: Publicly available from www.maximintegrated.com Authors: - Christian W. Zuckschwerdt <zany@triq.net> - valuable contributions by Jan M. Sendler <sendler@sendler.de> - ported to 2.6 by Aurelien Jarno <aurelien@aurel32.net> - with the help of Jean Delvare <jdelvare@suse.de> + - Christian W. Zuckschwerdt <zany@triq.net> + - valuable contributions by Jan M. Sendler <sendler@sendler.de> + - ported to 2.6 by Aurelien Jarno <aurelien@aurel32.net> + with the help of Jean Delvare <jdelvare@suse.de> Module Parameters ------------------ * polarity int - Output's polarity: 0 = active high, 1 = active low + Output's polarity: + + * 0 = active high, + * 1 = active low Description ----------- @@ -87,28 +106,31 @@ are used internally, however, these flags do get set and cleared as the actual temperature crosses the min or max settings (which by default are set to 75 and 80 degrees respectively). -Temperature Conversion: ------------------------ -DS1621 - 750ms (older devices may take up to 1000ms) -DS1625 - 500ms -DS1631 - 93ms..750ms for 9..12 bits resolution, respectively. -DS1721 - 93ms..750ms for 9..12 bits resolution, respectively. -DS1731 - 93ms..750ms for 9..12 bits resolution, respectively. +Temperature Conversion +---------------------- + +- DS1621 - 750ms (older devices may take up to 1000ms) +- DS1625 - 500ms +- DS1631 - 93ms..750ms for 9..12 bits resolution, respectively. +- DS1721 - 93ms..750ms for 9..12 bits resolution, respectively. +- DS1731 - 93ms..750ms for 9..12 bits resolution, respectively. Note: On the DS1621, internal access to non-volatile registers may last for 10ms or less (unverified on the other devices). -Temperature Accuracy: ---------------------- -DS1621: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1625: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1631: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1721: +/- 1.0 degree Celsius (from -10 to +85 degrees) -DS1731: +/- 1.0 degree Celsius (from -10 to +85 degrees) +Temperature Accuracy +-------------------- -Note: -Please refer to the device datasheets for accuracy at other temperatures. +- DS1621: +/- 0.5 degree Celsius (from 0 to +70 degrees) +- DS1625: +/- 0.5 degree Celsius (from 0 to +70 degrees) +- DS1631: +/- 0.5 degree Celsius (from 0 to +70 degrees) +- DS1721: +/- 1.0 degree Celsius (from -10 to +85 degrees) +- DS1731: +/- 1.0 degree Celsius (from -10 to +85 degrees) + +.. Note:: + + Please refer to the device datasheets for accuracy at other temperatures. Temperature Resolution: ----------------------- @@ -117,60 +139,67 @@ support, which is achieved via the R0 and R1 config register bits, where: R0..R1 ------ - 0 0 => 9 bits, 0.5 degrees Celsius - 1 0 => 10 bits, 0.25 degrees Celsius - 0 1 => 11 bits, 0.125 degrees Celsius - 1 1 => 12 bits, 0.0625 degrees Celsius -Note: -At initial device power-on, the default resolution is set to 12-bits. +== == =============================== +R0 R1 +== == =============================== + 0 0 9 bits, 0.5 degrees Celsius + 1 0 10 bits, 0.25 degrees Celsius + 0 1 11 bits, 0.125 degrees Celsius + 1 1 12 bits, 0.0625 degrees Celsius +== == =============================== + +.. Note:: + + At initial device power-on, the default resolution is set to 12-bits. The resolution mode for the DS1631, DS1721, or DS1731 can be changed from userspace, via the device 'update_interval' sysfs attribute. This attribute will normalize the range of input values to the device maximum resolution values defined in the datasheet as follows: +============= ================== =============== Resolution Conversion Time Input Range (C/LSB) (msec) (msec) ------------------------------------------------- +============= ================== =============== 0.5 93.75 0....94 0.25 187.5 95...187 0.125 375 188..375 0.0625 750 376..infinity ------------------------------------------------- +============= ================== =============== The following examples show how the 'update_interval' attribute can be -used to change the conversion time: - -$ cat update_interval -750 -$ cat temp1_input -22062 -$ -$ echo 300 > update_interval -$ cat update_interval -375 -$ cat temp1_input -22125 -$ -$ echo 150 > update_interval -$ cat update_interval -188 -$ cat temp1_input -22250 -$ -$ echo 1 > update_interval -$ cat update_interval -94 -$ cat temp1_input -22000 -$ -$ echo 1000 > update_interval -$ cat update_interval -750 -$ cat temp1_input -22062 -$ +used to change the conversion time:: + + $ cat update_interval + 750 + $ cat temp1_input + 22062 + $ + $ echo 300 > update_interval + $ cat update_interval + 375 + $ cat temp1_input + 22125 + $ + $ echo 150 > update_interval + $ cat update_interval + 188 + $ cat temp1_input + 22250 + $ + $ echo 1 > update_interval + $ cat update_interval + 94 + $ cat temp1_input + 22000 + $ + $ echo 1000 > update_interval + $ cat update_interval + 750 + $ cat temp1_input + 22062 + $ As shown, the ds1621 driver automatically adjusts the 'update_interval' user input, via a step function. Reading back the 'update_interval' value @@ -182,6 +211,7 @@ via the following function: g(x) = 0.5 * [minimum_conversion_time/x] where: - -> 'x' = the output from 'update_interval' - -> 'g(x)' = the resolution in degrees C per LSB. - -> 93.75ms = minimum conversion time + + - 'x' = the output from 'update_interval' + - 'g(x)' = the resolution in degrees C per LSB. + - 93.75ms = minimum conversion time |