Advertisement
Alarm
* ALM-A/B DISP & SEL. [Pin 25]
V
SS
Alarm B set time display
(Setting enabled)
(1) Entering alarm mode
Alarm A set time display (setting enabled): High level
Alarm B set time display (setting enabled): Low level
This pin should be left open in normal operation.
Applying a high or low level to this pin displays the set time for alarm A (high level) or alarm B (low level) and
enables the alarm time to be set. The display switches to set time display (with an initial value of 12:00 or 0:00) and
the colon and the corresponding alarm indicator (ALM INDICATOR) flash in synchronization.
(2) Adjusting the set time
The alarm time settings are adjusted by displaying the alarm whose setting is to be changed, and then inputting a
high or low level to the TIME SET INPUT pin (pin 20). We will refer to these latter operations as "+ input" and "–
input" in the remainder of this section.
The initial value of the display will be 12:00 (or 0:00) unless there was a previous setting, in which case that value is
displayed. The alarms are set in 1 minute increments, and the setting is changed by one minute each time a + input or
a – input is applied. Furthermore, if the + or – input is applied for more than 0.5 to 1.0 seconds the setting changes at
a speed of 20 msec per increment when 60 Hz is input to the 50/60 Hz INPUT pin, and at 17 msec per increment for
a 50 Hz input. Note that alarm output will start if the set time and the current time match during alarm setting.
(3) Enabling and disabling alarms
Use the following methods to enable and disable the alarms.
• Enabling an alarm
At the point that the set time for the alarm to be operated is displayed, that alarm is enabled, and the alarm
indicator (ALM INDICATOR) for that alarm is displayed.
• Disabling an alarm
When an alarms time setting is displayed, that alarm can be disabled by applying a low level to the MANUAL pin.
At this point the colon will blink continuously and the alarm indicator for the corresponding alarm will go out.
Note that the set time is maintained, i.e., is not reset.
(4) Alarm operating conditions
The alarm operates under either of the following conditions:
• If the alarm set time and the current time agree when alarm operation is enabled.
• If the alarm set time and the current time agree while setting the alarm time, i.e., while advancing or backing up the
alarm time setting.
(5) Alarm operation termination conditions
Alarm output stops if any of the following conditions are met.
• If a high or low level is applied to the MANUAL & SLEEP pin (pin 26).
• If there was a snooze input, i.e., if either a high or low level was applied to the CAL DISP & SNOOZE pin). Note
that alarm output will resume once the snooze setting period has elapsed.
• If a total time of 59 minutes (excluding the snooze interrupt periods) has passed since the start of the alarm output.
• If the other alarm starts operation during alarm output. (See item (7), "Output.")
• If the other alarm starts operation during an interruption of alarm output due to the snooze function. (See item (7),
"Output.")
LC85632
OPEN
NOP
(Current time display)
V
DD
Alarm A set time display
(Setting enabled)
No. 4659-21/34
Advertisement
