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Documentation / hwmon / lm75


Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.

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.
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