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>.

Debian                                            March 7, 2015                                        DS1307(4)