[linux-2.6-block.git] / Documentation / hwmon / lm95245

Kernel driver lm95245
==================

Supported chips:
  * TI LM95235
    Addresses scanned: I2C 0x18, 0x29, 0x4c
    Datasheet: Publicly available at the TI website
               http://www.ti.com/lit/ds/symlink/lm95235.pdf
  * TI / National Semiconductor LM95245
    Addresses scanned: I2C 0x18, 0x19, 0x29, 0x4c, 0x4d
    Datasheet: Publicly available at the TI website
               http://www.ti.com/lit/ds/symlink/lm95245.pdf


Author: Alexander Stein <alexander.stein@systec-electronic.com>

Description
-----------

LM95235 and LM95245 are 11-bit digital temperature sensors with a 2-wire System
Management Bus (SMBus) interface and TruTherm technology that can monitor
the temperature of a remote diode as well as its own temperature.
The chips can be used to very accurately monitor the temperature of
external devices such as microprocessors.

All temperature values are given in millidegrees Celsius. Local temperature
is given within a range of -127 to +127.875 degrees. Remote temperatures are
given within a range of -127 to +255 degrees. Resolution depends on
temperature input and range.

Each sensor has its own critical limit. Additionally, there is a relative
hysteresis value common to both critical limits. To make life easier to
user-space applications, two absolute values are exported, one for each
channel, but these values are of course linked. Only the local hysteresis
can be set from user-space, and the same delta applies to the remote
hysteresis.

The lm95245 driver can change its update interval to a fixed set of values.
It will round up to the next selectable interval. See the datasheet for exact
values. Reading sensor values more often will do no harm, but will return
'old' values.
Commit	Line	Data
	1	Kernel driver lm95245
	2	==================
	3
	4	Supported chips:
	5	* TI LM95235
	6	Addresses scanned: I2C 0x18, 0x29, 0x4c
	7	Datasheet: Publicly available at the TI website
	8	http://www.ti.com/lit/ds/symlink/lm95235.pdf
	9	* TI / National Semiconductor LM95245
	10	Addresses scanned: I2C 0x18, 0x19, 0x29, 0x4c, 0x4d
	11	Datasheet: Publicly available at the TI website
	12	http://www.ti.com/lit/ds/symlink/lm95245.pdf
	13
	14
	15	Author: Alexander Stein <alexander.stein@systec-electronic.com>
	16
	17	Description
	18	-----------
	19
	20	LM95235 and LM95245 are 11-bit digital temperature sensors with a 2-wire System
	21	Management Bus (SMBus) interface and TruTherm technology that can monitor
	22	the temperature of a remote diode as well as its own temperature.
	23	The chips can be used to very accurately monitor the temperature of
	24	external devices such as microprocessors.
	25
	26	All temperature values are given in millidegrees Celsius. Local temperature
	27	is given within a range of -127 to +127.875 degrees. Remote temperatures are
	28	given within a range of -127 to +255 degrees. Resolution depends on
	29	temperature input and range.
	30
	31	Each sensor has its own critical limit. Additionally, there is a relative
	32	hysteresis value common to both critical limits. To make life easier to
	33	user-space applications, two absolute values are exported, one for each
	34	channel, but these values are of course linked. Only the local hysteresis
	35	can be set from user-space, and the same delta applies to the remote
	36	hysteresis.
	37
	38	The lm95245 driver can change its update interval to a fixed set of values.
	39	It will round up to the next selectable interval. See the datasheet for exact
	40	values. Reading sensor values more often will do no harm, but will return
	41	'old' values.