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| 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. | ||