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R.Marek@sh.cvut.cz7f15b662005-05-26 12:42:19 +00001Kernel driver lm75
2==================
3
4Supported chips:
5 * National Semiconductor LM75
6 Prefix: 'lm75'
7 Addresses scanned: I2C 0x48 - 0x4f
8 Datasheet: Publicly available at the National Semiconductor website
9 http://www.national.com/
10 * Dallas Semiconductor DS75
11 Prefix: 'lm75'
12 Addresses scanned: I2C 0x48 - 0x4f
13 Datasheet: Publicly available at the Dallas Semiconductor website
14 http://www.maxim-ic.com/
15 * Dallas Semiconductor DS1775
16 Prefix: 'lm75'
17 Addresses scanned: I2C 0x48 - 0x4f
18 Datasheet: Publicly available at the Dallas Semiconductor website
19 http://www.maxim-ic.com/
20 * Maxim MAX6625, MAX6626
21 Prefix: 'lm75'
22 Addresses scanned: I2C 0x48 - 0x4b
23 Datasheet: Publicly available at the Maxim website
24 http://www.maxim-ic.com/
25 * Microchip (TelCom) TCN75
26 Prefix: 'lm75'
27 Addresses scanned: I2C 0x48 - 0x4f
28 Datasheet: Publicly available at the Microchip website
29 http://www.microchip.com/
30
31Author: Frodo Looijaard <frodol@dds.nl>
32
33Description
34-----------
35
36The LM75 implements one temperature sensor. Limits can be set through the
37Overtemperature Shutdown register and Hysteresis register. Each value can be
38set and read to half-degree accuracy.
39An alarm is issued (usually to a connected LM78) when the temperature
40gets higher then the Overtemperature Shutdown value; it stays on until
41the temperature falls below the Hysteresis value.
42All temperatures are in degrees Celsius, and are guaranteed within a
43range of -55 to +125 degrees.
44
45The LM75 only updates its values each 1.5 seconds; reading it more often
46will do no harm, but will return 'old' values.
47
48The LM75 is usually used in combination with LM78-like chips, to measure
49the temperature of the processor(s).
50
51The DS75, DS1775, MAX6625, and MAX6626 are supported as well.
52They are not distinguished from an LM75. While most of these chips
53have three additional bits of accuracy (12 vs. 9 for the LM75),
54the additional bits are not supported. Not only that, but these chips will
55not be detected if not in 9-bit precision mode (use the force parameter if
56needed).
57
58The TCN75 is supported as well, and is not distinguished from an LM75.
59
60The LM75 is essentially an industry standard; there may be other
61LM75 clones not listed here, with or without various enhancements,
62that are supported.
63
64The LM77 is not supported, contrary to what we pretended for a long time.
65Both chips are simply not compatible, value encoding differs.