Documentation/hwmon/lm75

   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   * National Semiconductor LM75A
  11     Prefix: 'lm75a'
  12     Addresses scanned: I2C 0x48 - 0x4f
  13     Datasheet: Publicly available at the National Semiconductor website
  14                http://www.national.com/
  15   * Dallas Semiconductor (now Maxim) DS75, DS1775, DS7505
  16     Prefixes: 'ds75', 'ds1775', 'ds7505'
  17     Addresses scanned: none
  18     Datasheet: Publicly available at the Maxim website
  19                http://www.maximintegrated.com/
  20   * Maxim MAX6625, MAX6626
  21     Prefixes: 'max6625', 'max6626'
  22     Addresses scanned: none
  23     Datasheet: Publicly available at the Maxim website
  24                http://www.maxim-ic.com/
  25   * Microchip (TelCom) TCN75
  26     Prefix: 'tcn75'
  27     Addresses scanned: none
  28     Datasheet: Publicly available at the Microchip website
  29                http://www.microchip.com/
  30   * Microchip MCP9800, MCP9801, MCP9802, MCP9803
  31     Prefix: 'mcp980x'
  32     Addresses scanned: none
  33     Datasheet: Publicly available at the Microchip website
  34                http://www.microchip.com/
  35   * Analog Devices ADT75
  36     Prefix: 'adt75'
  37     Addresses scanned: none
  38     Datasheet: Publicly available at the Analog Devices website
  39                http://www.analog.com/adt75
  40   * ST Microelectronics STDS75
  41     Prefix: 'stds75'
  42     Addresses scanned: none
  43     Datasheet: Publicly available at the ST website
  44                http://www.st.com/internet/analog/product/121769.jsp
  45   * Texas Instruments TMP100, TMP101, TMP105, TMP112, TMP75, TMP75C, TMP175, TMP275
  46     Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp112', 'tmp175', 'tmp75', 'tmp75c', 'tmp275'
  47     Addresses scanned: none
  48     Datasheet: Publicly available at the Texas Instruments website
  49                http://www.ti.com/product/tmp100
  50                http://www.ti.com/product/tmp101
  51                http://www.ti.com/product/tmp105
  52                http://www.ti.com/product/tmp112
  53                http://www.ti.com/product/tmp75
  54                http://www.ti.com/product/tmp75c
  55                http://www.ti.com/product/tmp175
  56                http://www.ti.com/product/tmp275
  57   * NXP LM75B
  58     Prefix: 'lm75b'
  59     Addresses scanned: none
  60     Datasheet: Publicly available at the NXP website
  61                http://www.nxp.com/documents/data_sheet/LM75B.pdf
  62
  63 Author: Frodo Looijaard <frodol@dds.nl>
  64
  65 Description
  66 -----------
  67
  68 The LM75 implements one temperature sensor. Limits can be set through the
  69 Overtemperature Shutdown register and Hysteresis register. Each value can be
  70 set and read to half-degree accuracy.
  71 An alarm is issued (usually to a connected LM78) when the temperature
  72 gets higher then the Overtemperature Shutdown value; it stays on until
  73 the temperature falls below the Hysteresis value.
  74 All temperatures are in degrees Celsius, and are guaranteed within a
  75 range of -55 to +125 degrees.
  76
  77 The driver caches the values for a period varying between 1 second for the
  78 slowest chips and 125 ms for the fastest chips; reading it more often
  79 will do no harm, but will return 'old' values.
  80
  81 The original LM75 was typically used in combination with LM78-like chips
  82 on PC motherboards, to measure the temperature of the processor(s). Clones
  83 are now used in various embedded designs.
  84
  85 The LM75 is essentially an industry standard; there may be other
  86 LM75 clones not listed here, with or without various enhancements,
  87 that are supported. The clones are not detected by the driver, unless
  88 they reproduce the exact register tricks of the original LM75, and must
  89 therefore be instantiated explicitly. Higher resolution up to 12-bit
  90 is supported by this driver, other specific enhancements are not.
  91
  92 The LM77 is not supported, contrary to what we pretended for a long time.
  93 Both chips are simply not compatible, value encoding differs.