Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
DS3231(4)		 BSD Kernel Interfaces Manual		     DS3231(4)

NAME
     ds3231 -- Extremely Accurate i2c-integrated RTC/TCXO/Crystal

SYNOPSIS
     device iic
     device iicbus
     device ds3231

DESCRIPTION
     The ds3231	is a low-cost, extremely accurate I2C realtime clock (RTC)
     with an integrated	temperature-compensated	crystal	oscillator (TCXO) and
     crystal.

     The device	incorporates a battery input and maintains accurate timekeep-
     ing when main power to the	device is interrupted.

     Access to ds3231 data is made with	the sysctl(8) interface:

     dev.ds3231.0.%desc: Maxim DS3231 RTC
     dev.ds3231.0.%driver: ds3231
     dev.ds3231.0.%location: addr=0xd0
     dev.ds3231.0.%pnpinfo: name=rtc compat=maxim,ds3231
     dev.ds3231.0.%parent: iicbus1
     dev.ds3231.0.temperature: 23.2C
     dev.ds3231.0.temp_conv: 0
     dev.ds3231.0.bbsqw: 0
     dev.ds3231.0.sqw_freq: 8192
     dev.ds3231.0.sqw_mode: interrupt
     dev.ds3231.0.32khz_enable:	1

     dev.ds3231.%d.temperature	The read-only value of the current temperature
				read by	the RTC.

     dev.ds3231.%d.temp_conv	Start a	new temperature	conversion.  When read
				as 1, a	temperature conversion is in progress.
				When read as 0 and then	set to 1, a tempera-
				ture conversion	is started.  The temperature
				conversion runs	automatically on power up and
				once every 64 seconds afterward.

     dev.ds3231.%d.bbsqw	If set to 1 and	dev.ds3231.%d.sqw_mode is set
				to square-wave,	battery-backed square-wave
				output is enabled.  If set to 0, the SQW pin
				will be	set to high impendance when the	RTC is
				being powered by battery.

     dev.ds3231.%d.sqw_freq	Select the frequency of	the SQW	pin when the
				square-wave output is enabled on
				dev.ds3231.%d.sqw_mode.	 It can	be set to 1,
				1024, 4096, and	8192.

     dev.ds3231.%d.sqw_mode	Set the	operation mode for the SQW pin.	 It
				can be set to 'interrupt' (default) or
				'square-wave'.	In interrupt mode, the SQW pin
				is used	to generate interrupts for the RTC
				alarms.	 In square-wave	mode, the SQW pin
				drives a square-wave of	dev.ds3231.%d.sqw_freq
				frequency.

     dev.ds3231.%d.32khz_enable
				Enable the 32kHz output.

     Please check the ds3231 datasheet for more	details.

     On	a device.hints(5) based	system,	such as	MIPS, these values are config-
     urable for	ds3231:

     hint.ds3231.%d.at	  The iicbus(4)	that the ds3231	is connected to.

     hint.ds3231.%d.addr  The 8-bit i2c	address	of ds3231.  The	default	8-bit
			  address for ds3231 is	0xd0.

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

     compatible	 Must always be	set to "maxim,ds3231".

     reg	 The 7-bit i2c address of ds3231.  The default 7-bit address
		 for ds3231 is 0x68.

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

HISTORY
     The ds3231	driver first appeared in FreeBSD 11.0.

AUTHORS
     The ds3231	driver and this	manual page were written by Luiz Otavio	O
     Souza <loos@FreeBSD.org>.

BSD			       February	12, 2016			   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=ds3231&sektion=4&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help