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 timekeeping
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 temperature 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 configurable 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.
|
|
