1 Kernel driver lm83 1 Kernel driver lm83
2 ================== 2 ==================
3 3
4 Supported chips: 4 Supported chips:
5 5
6 * National Semiconductor LM83 6 * National Semiconductor LM83
7 7
8 Prefix: 'lm83' 8 Prefix: 'lm83'
9 9
10 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 10 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
11 11
12 Datasheet: Publicly available at the Natio 12 Datasheet: Publicly available at the National Semiconductor website
13 13
14 http://www.national.com/pf/LM/L 14 http://www.national.com/pf/LM/LM83.html
15 15
16 * National Semiconductor LM82 16 * National Semiconductor LM82
17 17
18 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 18 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
19 19
20 Datasheet: Publicly available at the Natio 20 Datasheet: Publicly available at the National Semiconductor website
21 21
22 http://www.national.com/pf/LM/L 22 http://www.national.com/pf/LM/LM82.html
23 23
24 Author: Jean Delvare <jdelvare@suse.de> 24 Author: Jean Delvare <jdelvare@suse.de>
25 25
26 Description 26 Description
27 ----------- 27 -----------
28 28
29 The LM83 is a digital temperature sensor. It s 29 The LM83 is a digital temperature sensor. It senses its own temperature as
30 well as the temperature of up to three externa 30 well as the temperature of up to three external diodes. The LM82 is
31 a stripped down version of the LM83 that only 31 a stripped down version of the LM83 that only supports one external diode.
32 Both are compatible with many other devices su 32 Both are compatible with many other devices such as the LM84 and all
33 other ADM1021 clones. The main difference betw 33 other ADM1021 clones. The main difference between the LM83 and the LM84
34 in that the later can only sense the temperatu 34 in that the later can only sense the temperature of one external diode.
35 35
36 Using the adm1021 driver for a LM83 should wor 36 Using the adm1021 driver for a LM83 should work, but only two temperatures
37 will be reported instead of four. 37 will be reported instead of four.
38 38
39 The LM83 is only found on a handful of motherb 39 The LM83 is only found on a handful of motherboards. Both a confirmed
40 list and an unconfirmed list follow. If you ca 40 list and an unconfirmed list follow. If you can confirm or infirm the
41 fact that any of these motherboards do actuall 41 fact that any of these motherboards do actually have an LM83, please
42 contact us. Note that the LM90 can easily be m 42 contact us. Note that the LM90 can easily be misdetected as a LM83.
43 43
44 Confirmed motherboards: 44 Confirmed motherboards:
45 === ===== 45 === =====
46 SBS P014 46 SBS P014
47 SBS PSL09 47 SBS PSL09
48 === ===== 48 === =====
49 49
50 Unconfirmed motherboards: 50 Unconfirmed motherboards:
51 =========== ========== 51 =========== ==========
52 Gigabyte GA-8IK1100 52 Gigabyte GA-8IK1100
53 Iwill MPX2 53 Iwill MPX2
54 Soltek SL-75DRV5 54 Soltek SL-75DRV5
55 =========== ========== 55 =========== ==========
56 56
57 The LM82 is confirmed to have been found on mo 57 The LM82 is confirmed to have been found on most AMD Geode reference
58 designs and test platforms. 58 designs and test platforms.
59 59
60 The driver has been successfully tested by Mag 60 The driver has been successfully tested by Magnus Forsström, who I'd
61 like to thank here. More testers will be of co 61 like to thank here. More testers will be of course welcome.
62 62
63 The fact that the LM83 is only scarcely used c 63 The fact that the LM83 is only scarcely used can be easily explained.
64 Most motherboards come with more than just tem 64 Most motherboards come with more than just temperature sensors for
65 health monitoring. They also have voltage and 65 health monitoring. They also have voltage and fan rotation speed
66 sensors. This means that temperature-only chip 66 sensors. This means that temperature-only chips are usually used as
67 secondary chips coupled with another chip such 67 secondary chips coupled with another chip such as an IT8705F or similar
68 chip, which provides more features. Since syst 68 chip, which provides more features. Since systems usually need three
69 temperature sensors (motherboard, processor, p 69 temperature sensors (motherboard, processor, power supply) and primary
70 chips provide some temperature sensors, the se 70 chips provide some temperature sensors, the secondary chip, if needed,
71 won't have to handle more than two temperature 71 won't have to handle more than two temperatures. Thus, ADM1021 clones
72 are sufficient, and there is no need for a fou 72 are sufficient, and there is no need for a four temperatures sensor
73 chip such as the LM83. The only case where usi 73 chip such as the LM83. The only case where using an LM83 would make
74 sense is on SMP systems, such as the above-men 74 sense is on SMP systems, such as the above-mentioned Iwill MPX2,
75 because you want an additional temperature sen 75 because you want an additional temperature sensor for each additional
76 CPU. 76 CPU.
77 77
78 On the SBS P014, this is different, since the 78 On the SBS P014, this is different, since the LM83 is the only hardware
79 monitoring chipset. One temperature sensor is 79 monitoring chipset. One temperature sensor is used for the motherboard
80 (actually measuring the LM83's own temperature 80 (actually measuring the LM83's own temperature), one is used for the
81 CPU. The two other sensors must be used to mea 81 CPU. The two other sensors must be used to measure the temperature of
82 two other points of the motherboard. We suspec 82 two other points of the motherboard. We suspect these points to be the
83 north and south bridges, but this couldn't be 83 north and south bridges, but this couldn't be confirmed.
84 84
85 All temperature values are given in degrees Ce 85 All temperature values are given in degrees Celsius. Local temperature
86 is given within a range of 0 to +85 degrees. R 86 is given within a range of 0 to +85 degrees. Remote temperatures are
87 given within a range of 0 to +125 degrees. Res 87 given within a range of 0 to +125 degrees. Resolution is 1.0 degree,
88 accuracy is guaranteed to 3.0 degrees (see the 88 accuracy is guaranteed to 3.0 degrees (see the datasheet for more
89 details). 89 details).
90 90
91 Each sensor has its own high limit, but the cr 91 Each sensor has its own high limit, but the critical limit is common to
92 all four sensors. There is no hysteresis mecha 92 all four sensors. There is no hysteresis mechanism as found on most
93 recent temperature sensors. 93 recent temperature sensors.
94 94
95 The lm83 driver will not update its values mor 95 The lm83 driver will not update its values more frequently than every
96 other second; reading them more often will do 96 other second; reading them more often will do no harm, but will return
97 'old' values. 97 'old' values.
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