Real-time clock control – Rainbow Electronics DS2422 User Manual
Page 16
DS2422
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Register Details
BIT DESCRIPTION
BIT(S)
DEFINITION
EDLA: Enable Data Low
Alarm
b0
This bit controls whether, during a mission, the Data Low Alarm Flag
DLF may be set, if a data value from the serial data interface is equal to
or lower than the value in the Data Low Alarm Threshold Register. If
EDLA is 1, data low alarms are enabled. If EDLA is 0, data low alarms
are not generated.
EDHA: Enable Data High
Alarm
b1
This bit controls whether, during a mission, the Data High Alarm Flag
DHF may be set, if a data value from the serial data interface is equal to
or higher than the value in the Data High Alarm Threshold Register. If
EDHA is 1, data high alarms are enabled. If EDHA is 0, data high
alarms are not generated.
REAL-TIME CLOCK CONTROL
To minimize the power consumption of a battery-operated datalogger, the RTC oscillator should be turned off when
device is not in use. The oscillator on/off bit is located in the RTC control register. This register also includes the
EHSS bit, which determines whether the sample rate is specified in seconds or minutes.
RTC Control Register Bitmap
ADDR
b7
b6
b5
b4
b3
b2
b1
b0
0212h
0
0
0
0
0
0
EHSS
EOSC
During a mission, there is only read access to this register. Bits 2-7 have no function. They always read 0 and
cannot be written to 1.
Register Details
BIT DESCRIPTION
BIT(S)
DEFINITION
EOSC: Enable Oscillator
b0
This bit controls the crystal oscillator of the RTC. When set to logic 1,
the oscillator will start operation. When written to logic 0, the oscillator
stops and the device is in a low-power data retention mode. This bit
must be 1 for normal operation. A temperature conversion or serial
data input must not be attempted while the RTC oscillator is stopped.
This will cause the device to enter into an undefined state, requiring a
power-on reset and restore of the trim settings to recover.
EHSS: Enable High Speed
Sample
b1
This bit controls the speed of the Sample Rate counter. When set to
logic 0, the sample rate is specified in minutes. When set to logic 1, the
sample rate is specified in seconds.