NAME
lmtemp —
National Semiconductor LM75, LM77 and
compatible hardware monitors
SYNOPSIS
lmtemp0 at iic? addr 0x48 flags 0x0000
DESCRIPTION
Thelmtemp 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
HISTORY
The lmtemp device appeared in
NetBSD 4.0.
BUGS
Interrupt support is unimplemented.