ds1307 (4)

Leading comments

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
   ...

(The comments found at the beginning of the groff file "man4/ds1307.4freebsd".)

NAME

ds1307 - 64 x 8, serial, i2c real-time clock

SYNOPSIS

device iic device iicbus device ds1307

DESCRIPTION

The serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM.

The 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.

Access to settings is made with the sysctl(8) interface:

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

dev.ds1307.%d.sqwe

If set to 1, the SQW pin drives a square-wave of dev.ds1307.%d.sqw_freq frequency. If set to 0, the output level of SQW pin is controlled by dev.ds1307.%d.sqw_out

dev.ds1307.%d.sqw_freq

Select the frequency of the SQW pin when the square-wave output is enabled on dev.ds1307.%d.sqwe It can be set to 1, 4096, 8192 and 32768.

dev.ds1307.%d.sqw_out

Set the output level of the SQW pin when dev.ds1307.%d.sqwe is set to 0.

Please check the datasheet for more details.

On a device.hints5 based system, such as MIPS these values are configurable for :

hint.ds1307.%d.at

The iicbus(4) that the is connected to.

hint.ds1307.%d.addr

The i2c address of .

On a FDT(4) based system the following properties must be set:

compatible

Must always be set to "dallas,ds1307" or "maxim,ds1307".

reg

The i2c address of . The default address for is 0xd0.

SEE ALSO

fdt(4), iic(4), iicbus(4), sysctl(8)

HISTORY

The driver first appeared in Fx 11.0 .

AUTHORS

An -nosplit The driver and this manual page were written by An Luiz Otavio O Souza Aq Mt loos@FreeBSD.org .