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.