.\" $NetBSD: mcp980x.4,v 1.6 2016/07/26 08:05:51 rkujawa Exp $
.\"
.\" Copyright (c) 2013 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Radoslaw Kujawa.
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.Dd July 26, 2016
.Dt MCP980X 4
.Os
.Sh NAME
.Nm mcp980x
.Nd Microchip 9800/1/2/3 I2C temperature sensor driver
.Sh SYNOPSIS
.Cd "mcp980x* at iic? addr 0x48"
.Sh DESCRIPTION
The
.Nm
driver provides support for the MCP980x series of temperature sensors.
It allows reporting ambient temperature through the
.Xr envsys 4
API.
.Sh SYSCTL VARIABLES
The following
.Xr sysctl 3
variable are provided:
.Bl -tag -width machdep.mcp980x0.hysteresis
.It Va machdep.mcp980x0.res
ADC resolution (integer).
Valid values are 0-3, where 0 is 9-bit (0.5 Celsius degree) and 3 is 12-bit
(0.0625 Celsius degree) resolution.
.It Va machdep.mcp980x0.templimit
If the ambient temperature exceeds this limit, the chip asserts an alert line
(integer).
.It Va machdep.mcp980x0.hysteresis
Hysteresis for temperature limit (integer).
.El
.Sh SEE ALSO
.Xr envsys 4
.Sh HISTORY
The
.Nm
device first appeared in
.Nx 7.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Radoslaw Kujawa Aq Mt radoslaw.kujawa@gmail.com .
.Sh CAVEATS
MCP9804 and MCP9805 chip are different and is supported by the
.Xr sdtemp 4
driver.
.Pp
The MCP980x chip supports hysteresis and temperature limit values with a
resolution of 0.5 Celsius degree, however the
.Nm
driver supports setting only integer values.