About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / hwmon / lm75

Based on kernel version 2.6.26. Page generated on 2008-07-16 21:12 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	  * 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[AT]dds[DOT]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.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.