LM(4)

NAME
lm - National Semiconductor LM78/79/81 temperature, voltage, and fan sensor

SYNOPSIS
lm0 at isa? port 0x290
lm1 at isa? port 0x280
lm2 at isa? port 0x310
lm* at iic?
lm* at wbsio?

DESCRIPTION
The lm driver provides support for the National Semiconductor LM78/79/81 hardware monitors and register compatible chips to be used with the sysctl(8) interface.

The original LM78 hardware monitor supports 11 sensors:
Sensor | Units | Typical Use
IN0 | uV DC | Core voltage
IN1 | uV DC | Unknown
IN2 | uV DC | +3.3V
IN3 | uV DC | +5V
IN4 | uV DC | +12V
IN5 | uV DC | -12V
IN6 | uV DC | -5V
Temp | uK | Motherboard Temperature
Fan0 | RPM | Fan
Fan1 | RPM | Chassis Fan
Fan2 | RPM | Fan

For other devices, sensors' names and numbers will be different.

HARDWARE
Chips supported by the lm driver include:

-   ASUS AS99127F
-   National Semiconductor LM78 and LM78-J
-   National Semiconductor LM79
-   National Semiconductor LM81
-   Nuvoton NCT6776F
-   Winbond W83627HF, W83627THF, W83637HF and W83697HF
-   Winbond W83627DHG, W83627UHG and W83627EHF
-   Winbond W83781D, W83782D and W83783S
-   Winbond W83791D, W83791SD and W83792D

Some devices can attach to both iic(4) and isa(4); others can only attach to either one or the other. If the lm driver detects a device attaching to both iic(4) and isa(4), it will detach the device from iic(4).

SEE ALSO
iic(4), isa(4), wbsio(4), sensorsd(8), sysctl(8)

HISTORY
The lm driver first appeared in NetBSD 1.5; OpenBSD support was added in OpenBSD 3.4.

AUTHORS
-nosplit The lm driver was written by Bill Squier and ported to OpenBSD 3.4 by Alexander Yurchenko <grange@openbsd.org>. The driver was largely rewritten for OpenBSD 3.9 by Mark Kettenis <kettenis@openbsd.org>.

CAVEATS
Some vendors connect these chips to non-standard thermal diodes and resistors. This will result in bogus sensor values.

BUGS
Interrupt support is unimplemented.

There are currently no known pnpbios IDs assigned to LM chips.

This driver attaches to the Winbond W83791SD chip even though that chip does not have any sensors.