| Guenter Roeck | e1eb490 | 2013-03-10 16:54:19 -0700 | [diff] [blame] | 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. |