5 * Texas Instruments LM73
7 Addresses scanned: I2C 0x48, 0x49, 0x4a, 0x4c, 0x4d, and 0x4e
8 Datasheet: Publicly available at the Texas Instruments website
9 http://www.ti.com/product/lm73
11 Author: Guillaume Ligneul <guillaume.ligneul@gmail.com>
12 Documentation: Chris Verges <kg4ysn@gmail.com>
18 The LM73 is a digital temperature sensor. All temperature values are
19 given in degrees Celsius.
21 Measurement Resolution Support
22 ------------------------------
24 The LM73 supports four resolutions, defined in terms of degrees C per
25 LSB: 0.25, 0.125, 0.0625, and 0.3125. Changing the resolution mode
26 affects the conversion time of the LM73's analog-to-digital converter.
27 From userspace, the desired resolution can be specified as a function of
28 conversion time via the 'update_interval' sysfs attribute for the
29 device. This attribute will normalize ranges of input values to the
30 maximum times defined for the resolution in the datasheet.
32 Resolution Conv. Time Input Range
34 --------------------------------------
38 0.03125 112 57..infinity
39 --------------------------------------
41 The following examples show how the 'update_interval' attribute can be
42 used to change the conversion time:
44 $ echo 0 > update_interval
50 $ echo 22 > update_interval
56 $ echo 56 > update_interval
62 $ echo 85 > update_interval
68 As shown here, the lm73 driver automatically adjusts any user input for
69 'update_interval' via a step function. Reading back the
70 'update_interval' value after a write operation will confirm the
71 conversion time actively in use.
73 Mathematically, the resolution can be derived from the conversion time
74 via the following function:
76 g(x) = 0.250 * [log(x/14) / log(2)]
78 where 'x' is the output from 'update_interval' and 'g(x)' is the
79 resolution in degrees C per LSB.