LMTEMP(4)

NAME
lmtemp - National Semiconductor LM75, LM77 and compatible hardware monitors

SYNOPSIS
lmtemp0 at iic? addr 0x48 flags 0x0000

DESCRIPTION
The lmtemp driver provides support for the National Semiconductor LM on iicbus series temperature sensors and register compatible chips.

Each device is specified by the value of the address and flags.
Device | addr | flags
LM75 | 0x48 - 0x4f | 0x0000
LM75A | 0x48 - 0x4f | 0x0000
DS75 | 0x48 - 0x4f | 0x0001
LM77 | 0x48 - 0x4b | 0x0002

HARDWARE
Chips supported by the lmtemp driver include:
Device | Range | Resolution
National Semiconductor LM75 | -55 – +125 | 0.5 degC
Texas Instruments LM75A | -55 – +125 | 0.5 degC
Dallas Semiconductor DS75 | -55 – +125 | 0.0625 degC
National Semiconductor LM77 | -55 – +130 | 0.5 degC

The LM75, LM75A, and DS75 have a programmable high temperature limit. When this is exceeded, the device asserts an over-temperature output.

The LM77 has programmable low and high temperature limits. Exceeding either of these causes the device to assert an interrupt output. It also has a programmable critical high temperature limit, and exceeding this causes the device to assert a separate critical alarm output.

The sensor and limit values are made available through the envstat(8) interface.

SEE ALSO
envsys(4), envstat(8)

HISTORY
The lmtemp device appeared in NetBSD 4.0.

BUGS
Interrupt support is unimplemented.