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 <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 March 7, 2015 FreeBSD 14.1-RELEASE-p8