1.\" $OpenBSD: owsbm.4,v 1.6 2013/07/16 16:05:49 schwarze Exp $ 2.\" 3.\" Copyright (c) 2007 Aaron Linville <aaron@linville.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: July 16 2013 $ 18.Dt OWSBM 4 19.Os 20.Sh NAME 21.Nm owsbm 22.Nd 1-Wire smart battery monitor device 23.Sh SYNOPSIS 24.Cd "owsbm* at onewire?" 25.Sh DESCRIPTION 26The 27.Nm 28driver provides support for the 1-Wire smart battery monitor. 29The sensor possesses a temperature sensor, an A/D converter for measuring both 30battery voltage and current, a current accumulator of both incoming and 31outgoing current, an elapsed time and 40 bytes of nonvolatile EEPROM. 32.Pp 33Only the three voltages (VDD, VAD, CR) and temperature are accessible by 34the 35.Xr sysctl 8 36interface. 37.Pp 38The following chips are supported by the driver: 39.Pp 40.Bl -bullet -compact -offset indent 41.It 42Maxim/Dallas DS2438 43.El 44.Sh MEASURING CURRENT 45The sensor does not measure current directly. 46Instead it measures the voltage across the Rsens pins. 47.Bd -literal -offset indent 48I = Voltage CR / Rsens (where Rsens is in Ohms) 49.Ed 50.Sh SEE ALSO 51.Xr intro 4 , 52.Xr onewire 4 , 53.Xr owtemp 4 , 54.Xr sysctl 8 55.Sh HISTORY 56The 57.Nm 58driver first appeared in 59.Ox 4.1 . 60.Sh AUTHORS 61.An -nosplit 62The 63.Nm 64driver was written by 65.An Aaron Linville Aq Mt aaron@linville.org . 66