DS1307(4)              FreeBSD Kernel Interfaces Manual              DS1307(4)

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

SYNOPSIS
     device iic
     device iicbus
     device ds1307

DESCRIPTION
     The ds1307 serial real-time clock (RTC) is a low-power, full binary-coded
     decimal (BCD) clock/calendar plus 56 bytes of NV SRAM.

     The ds1307 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 ds1307 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 ds1307 datasheet for more details.

     On a device.hints(5) based system, such as MIPS, these values are
     configurable for ds1307:

     hint.ds1307.%d.at        The iicbus(4) that the ds1307 is connected to.

     hint.ds1307.%d.addr      The i2c address of ds1307.

     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 ds1307.  The default address for
                     ds1307 is 0xd0.

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

HISTORY
     The ds1307 driver first appeared in FreeBSD 11.0.

AUTHORS
     The ds1307 driver and this manual page were written by Luiz Otavio O
     Souza <loos@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6          March 7, 2015         FreeBSD 13.1-RELEASE-p6