1 Kernel driver lm78
2 ==================
3
4 Supported chips:
5
6 * National Semiconductor LM78 / LM78-J
7
8 Prefix: 'lm78'
9
10 Addresses scanned: I2C 0x28 - 0x2f, ISA 0x
11
12 Datasheet: Publicly available at the Natio
13
14 http://www.national.com/
15
16 * National Semiconductor LM79
17
18 Prefix: 'lm79'
19
20 Addresses scanned: I2C 0x28 - 0x2f, ISA 0x
21
22 Datasheet: Publicly available at the Natio
23
24 http://www.national.com/
25
26
27 Authors:
28 - Frodo Looijaard <frodol@dds.nl>
29 - Jean Delvare <jdelvare@suse.de>
30
31 Description
32 -----------
33
34 This driver implements support for the Nationa
35 and LM79. They are described as 'Microprocesso
36
37 There is almost no difference between the thre
38 the LM78 and LM78-J are exactly identical. The
39 which is used to report the lower voltages new
40 From here on, LM7* means either of these three
41
42 The LM7* implements one temperature sensor, th
43 seven voltage sensors, VID lines, alarms, and
44
45 Temperatures are measured in degrees Celsius.
46 when the Overtemperature Shutdown limit is cro
47 as soon as it drops below the Hysteresis value
48 can be found by setting the Hysteresis value t
49 this case, alarms are issued during all the ti
50 is above the Overtemperature Shutdown value. M
51 between -55 and +125 degrees, with a resolutio
52
53 Fan rotation speeds are reported in RPM (rotat
54 triggered if the rotation speed has dropped be
55 readings can be divided by a programmable divi
56 the readings more range or accuracy. Not all R
57 represented, so some rounding is done. With a
58 representable value is around 2600 RPM.
59
60 Voltage sensors (also known as IN sensors) rep
61 An alarm is triggered if the voltage has cross
62 or maximum limit. Note that minimum in this ca
63 zero'; this is important for negative voltage
64 inputs can measure voltages between 0 and 4.08
65 of 0.016 volt.
66
67 The VID lines encode the core voltage value: t
68 should work with. This is hardcoded by the mai
69 It is a value in volts. When it is unconnected
70 value 3.50 V here.
71
72 If an alarm triggers, it will remain triggered
73 is read at least once. This means that the cau
74 already have disappeared! Note that in the cur
75 hardware registers are read whenever any data
76 than 1.5 seconds since the last update). This
77 miss once-only alarms.
78
79 The LM7* only updates its values each 1.5 seco
80 will do no harm, but will return 'old' values.
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