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Diffstat (limited to 'Documentation/hwmon/lm75')
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diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75 new file mode 100644 index 00000000000..8e6356fe05d --- /dev/null +++ b/Documentation/hwmon/lm75 @@ -0,0 +1,65 @@ +Kernel driver lm75 +================== + +Supported chips: + * National Semiconductor LM75 + Prefix: 'lm75' + Addresses scanned: I2C 0x48 - 0x4f + Datasheet: Publicly available at the National Semiconductor website + http://www.national.com/ + * Dallas Semiconductor DS75 + Prefix: 'lm75' + Addresses scanned: I2C 0x48 - 0x4f + Datasheet: Publicly available at the Dallas Semiconductor website + http://www.maxim-ic.com/ + * Dallas Semiconductor DS1775 + Prefix: 'lm75' + Addresses scanned: I2C 0x48 - 0x4f + Datasheet: Publicly available at the Dallas Semiconductor website + http://www.maxim-ic.com/ + * Maxim MAX6625, MAX6626 + Prefix: 'lm75' + Addresses scanned: I2C 0x48 - 0x4b + Datasheet: Publicly available at the Maxim website + http://www.maxim-ic.com/ + * Microchip (TelCom) TCN75 + Prefix: 'lm75' + Addresses scanned: I2C 0x48 - 0x4f + Datasheet: Publicly available at the Microchip website + http://www.microchip.com/ + +Author: Frodo Looijaard <frodol@dds.nl> + +Description +----------- + +The LM75 implements one temperature sensor. Limits can be set through the +Overtemperature Shutdown register and Hysteresis register. Each value can be +set and read to half-degree accuracy. +An alarm is issued (usually to a connected LM78) when the temperature +gets higher then the Overtemperature Shutdown value; it stays on until +the temperature falls below the Hysteresis value. +All temperatures are in degrees Celsius, and are guaranteed within a +range of -55 to +125 degrees. + +The LM75 only updates its values each 1.5 seconds; reading it more often +will do no harm, but will return 'old' values. + +The LM75 is usually used in combination with LM78-like chips, to measure +the temperature of the processor(s). + +The DS75, DS1775, MAX6625, and MAX6626 are supported as well. +They are not distinguished from an LM75. While most of these chips +have three additional bits of accuracy (12 vs. 9 for the LM75), +the additional bits are not supported. Not only that, but these chips will +not be detected if not in 9-bit precision mode (use the force parameter if +needed). + +The TCN75 is supported as well, and is not distinguished from an LM75. + +The LM75 is essentially an industry standard; there may be other +LM75 clones not listed here, with or without various enhancements, +that are supported. + +The LM77 is not supported, contrary to what we pretended for a long time. +Both chips are simply not compatible, value encoding differs. |