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Commit | Line | Data |
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7f15b664 RM |
1 | Kernel driver lm75 |
2 | ================== | |
3 | ||
4 | Supported 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 | ||
31 | Author: Frodo Looijaard <frodol@dds.nl> | |
32 | ||
33 | Description | |
34 | ----------- | |
35 | ||
36 | The LM75 implements one temperature sensor. Limits can be set through the | |
37 | Overtemperature Shutdown register and Hysteresis register. Each value can be | |
38 | set and read to half-degree accuracy. | |
39 | An alarm is issued (usually to a connected LM78) when the temperature | |
40 | gets higher then the Overtemperature Shutdown value; it stays on until | |
41 | the temperature falls below the Hysteresis value. | |
42 | All temperatures are in degrees Celsius, and are guaranteed within a | |
43 | range of -55 to +125 degrees. | |
44 | ||
45 | The LM75 only updates its values each 1.5 seconds; reading it more often | |
46 | will do no harm, but will return 'old' values. | |
47 | ||
48 | The LM75 is usually used in combination with LM78-like chips, to measure | |
49 | the temperature of the processor(s). | |
50 | ||
51 | The DS75, DS1775, MAX6625, and MAX6626 are supported as well. | |
52 | They are not distinguished from an LM75. While most of these chips | |
53 | have three additional bits of accuracy (12 vs. 9 for the LM75), | |
54 | the additional bits are not supported. Not only that, but these chips will | |
55 | not be detected if not in 9-bit precision mode (use the force parameter if | |
56 | needed). | |
57 | ||
58 | The TCN75 is supported as well, and is not distinguished from an LM75. | |
59 | ||
60 | The LM75 is essentially an industry standard; there may be other | |
61 | LM75 clones not listed here, with or without various enhancements, | |
62 | that are supported. | |
63 | ||
64 | The LM77 is not supported, contrary to what we pretended for a long time. | |
65 | Both chips are simply not compatible, value encoding differs. |