cd1772ab61
Many thanks to ian who gently provided me the DS1307 breakout board. Tested on: Raspberry pi Differential Revision: https://reviews.freebsd.org/D2022 Reviewed by: rpaulo
132 lines
3.5 KiB
Groff
132 lines
3.5 KiB
Groff
.\"
|
|
.\" Copyright (c) 2015 Luiz Otavio O Souza <loos@freebsd.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 7, 2015
|
|
.Dt DS1307 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ds1307
|
|
.Nd 64 x 8, serial, i2c real-time clock
|
|
.Sh SYNOPSIS
|
|
.Cd "device iic"
|
|
.Cd "device iicbus"
|
|
.Cd "device ds1307"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD)
|
|
clock/calendar plus 56 bytes of NV SRAM.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
has a built-in power-sense circuit that detects power failures and
|
|
automatically switches to the backup supply.
|
|
Timekeeping operation continues while the part operates from the backup supply.
|
|
.Pp
|
|
Access to
|
|
.Nm
|
|
settings is made with the
|
|
.Xr sysctl 8
|
|
interface:
|
|
.Bd -literal
|
|
dev.ds1307.0.%desc: Maxim DS1307 RTC
|
|
dev.ds1307.0.%driver: ds1307
|
|
dev.ds1307.0.%location: addr=0xd0
|
|
dev.ds1307.0.%pnpinfo: name=rtc compat=maxim,ds1307
|
|
dev.ds1307.0.%parent: iicbus1
|
|
dev.ds1307.0.sqwe: 1
|
|
dev.ds1307.0.sqw_freq: 32768
|
|
dev.ds1307.0.sqw_out: 0
|
|
.Ed
|
|
.Bl -tag -width ".Va dev.ds1307.%d.sqw_freq"
|
|
.It Va dev.ds1307.%d.sqwe
|
|
If set to 1, the SQW pin drives a square-wave of
|
|
.Va dev.ds1307.%d.sqw_freq
|
|
frequency.
|
|
If set to 0, the output level of SQW pin is controlled by
|
|
.Va dev.ds1307.%d.sqw_out .
|
|
.It Va dev.ds1307.%d.sqw_freq
|
|
Select the frequency of the SQW pin when the square-wave output is enabled on
|
|
.Va dev.ds1307.%d.sqwe .
|
|
It can be set to 1, 4096, 8192 and 32768.
|
|
.It Va dev.ds1307.%d.sqw_out
|
|
Set the output level of the SQW pin when
|
|
.Va dev.ds1307.%d.sqwe
|
|
is set to 0.
|
|
.El
|
|
.Pp
|
|
Please check the
|
|
.Nm
|
|
datasheet for more details.
|
|
.Pp
|
|
On a
|
|
.Xr device.hints 5
|
|
based system, such as
|
|
.Li MIPS ,
|
|
these values are configurable for
|
|
.Nm :
|
|
.Bl -tag -width ".Va hint.ds1307.%d.addr"
|
|
.It Va hint.ds1307.%d.at
|
|
The
|
|
.Xr iicbus 4
|
|
that the
|
|
.Nm
|
|
is connected to.
|
|
.It Va hint.ds1307.%d.addr
|
|
The i2c address of
|
|
.Nm .
|
|
.El
|
|
.Pp
|
|
On a
|
|
.Xr FDT 4
|
|
based system the following properties must be set:
|
|
.Bl -tag -width ".Va compatible"
|
|
.It Va compatible
|
|
Must always be set to "dallas,ds1307" or "maxim,ds1307".
|
|
.It Va reg
|
|
The i2c address of
|
|
.Nm .
|
|
The default address for
|
|
.Nm
|
|
is 0xd0.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr fdt 4 ,
|
|
.Xr iic 4 ,
|
|
.Xr iicbus 4 ,
|
|
.Xr sysctl 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver first appeared in
|
|
.Fx 11.0 .
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The
|
|
.Nm
|
|
driver and this manual page were written by
|
|
.An Luiz Otavio O Souza Aq Mt loos@FreeBSD.org .
|