Manual browser: lmenv(4)

LMENV(4) Kernel Interfaces Manual LMENV(4)


lmenvNational Semiconductor LM81, LM87, and compatible hardware monitors


lmenv0 at iic0 addr 0x2c: ADM9240 rev 2


The lmenv driver provides support for the National Semiconductor LM87, National Semiconductor LM81, Analog Devices ADM9240, and Dallas Semiconductor DS1780 iicbus hardware monitors. Sensor values are reported through the envstat(8) interface.

The lmenv supports the following voltage, temperature, and fan speed sensors:

Sensor Type
+2.5Vin Volts DC
Vccp1 Volts DC
+Vcc Volts DC
+5Vin/Vcc Volts DC
+12Vin Volts DC
Vccp2 Volts DC
External Temperature
Internal Temperature
FAN1 Speed
FAN2 Speed
On the LM87 monitor, AIN1 and AIN2 Volts DC sensors may replace either, or both of the FAN1 and FAN2 speed sensors, respectively.


The lmenv driver first appeared in OpenBSD 3.9. NetBSD support was added in NetBSD 7.0.


The lmenv driver was written for OpenBSD by Mark Kettenis <>, and ported to NetBSD by Julian Coleman <>.


High and low sensor limits are not supported.

Interrupt support is not implemented.

October 14, 2013 NetBSD 7.0