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e1eb4906 GR |
1 | Kernel driver lm95234 |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
5 | * National Semiconductor / Texas Instruments LM95234 | |
6 | Addresses scanned: I2C 0x18, 0x4d, 0x4e | |
7 | Datasheet: Publicly available at the Texas Instruments website | |
8 | http://www.ti.com/product/lm95234 | |
9 | ||
10 | ||
11 | Author: Guenter Roeck <linux@roeck-us.net> | |
12 | ||
13 | Description | |
14 | ----------- | |
15 | ||
16 | LM95234 is an 11-bit digital temperature sensor with a 2-wire System Management | |
17 | Bus (SMBus) interface and TrueTherm technology that can very accurately monitor | |
18 | the temperature of four remote diodes as well as its own temperature. | |
19 | The four remote diodes can be external devices such as microprocessors, | |
20 | graphics processors or diode-connected 2N3904s. The LM95234's TruTherm | |
21 | beta compensation technology allows sensing of 90 nm or 65 nm process | |
22 | thermal diodes accurately. | |
23 | ||
24 | All temperature values are given in millidegrees Celsius. Temperature | |
25 | is provided within a range of -127 to +255 degrees (+127.875 degrees for | |
26 | the internal sensor). Resolution depends on temperature input and range. | |
27 | ||
28 | Each sensor has its own maximum limit, but the hysteresis is common to all | |
29 | channels. The hysteresis is configurable with the tem1_max_hyst attribute and | |
30 | affects the hysteresis on all channels. The first two external sensors also | |
31 | have a critical limit. | |
32 | ||
33 | The lm95234 driver can change its update interval to a fixed set of values. | |
34 | It will round up to the next selectable interval. See the datasheet for exact | |
35 | values. Reading sensor values more often will do no harm, but will return | |
36 | 'old' values. |