Operation Guide 3580
EN-9
Alarm Mode
C
Dual Time Mode
C
You can also find
information about
operational procedures
at the CASIO website.
https://s.casio.jp/mw/
en/3580/
EN-8
Selecting a Mode
x Press C to change from mode to mode.
x In any mode (except when a setting screen is on the display), press B to illuminate
the face of the watch.
Timekeeping Mode
Timer Mode
Stopwatch Mode
C
C C
EN-7
EN-6
Watch Features
You can also find information
about operational procedures
at the CASIO website.
https://s.casio.jp/mw/en/3580/
◆
Stopwatch
◆
Timer
◆
Alarm
◆
Dual Time
EN-5EN-4
Alarm .............................................................................................................. EN-22
To set an alarm time ...................................................................................EN-24
To test the alarm .........................................................................................EN-27
To turn Alarms 2 and 3, and the Hourly Time Signal on and off..................EN-27
To select the operation of Alarm 1 ..............................................................EN-29
Dual Time ....................................................................................................... EN-30
To set the Dual Time ...................................................................................EN-31
Illumination .................................................................................................... EN-33
To illuminate the display .............................................................................EN-33
To specify the illumination duration ............................................................EN-34
Reference ...................................................................................................... EN-35
To turn the button operation tone on and off ..............................................EN-36
Specifications ................................................................................................ EN-38
EN-3
Contents
About This Manual .......................................................................................... EN-2
Watch Features ............................................................................................... EN-6
Selecting a Mode ............................................................................................ EN-8
Timekeeping .................................................................................................. EN-10
To set the time and date .............................................................................EN-11
To toggle the Timekeeping Mode time between DST and
Standard Time.........................................................................................EN-14
To toggle between 12-hour and 24-hour timekeeping ................................EN-15
Stopwatch ...................................................................................................... EN-16
To measure times with the stopwatch ........................................................EN-17
Timer .............................................................................................................. EN-18
To use the timer ..........................................................................................EN-19
To set up the timer .....................................................................................EN-20
EN-2
About This Manual
x Button operations are indicated using the letters shown
in the illustration.
x Note that the product illustrations in this manual are
intended for reference only, and so the actual product
may appear somewhat different than depicted by an
illustration.
x Each section of this manual provides you with the
information you need to perform operations in each
mode. Further details and technical information can be
found in the “Reference” section.
EN-1
ENGLISH
You can also find information about
operational procedures at the CASIO website.
https://s.casio.jp/mw/en/3580/
MA2503-EA
© 2025 CASIO COMPUTER CO., LTD.
Published: 3/2025
Operation Guide 3580
EN-19
To use the timer
Press D while in the Timer Mode to start the countdown timer.
x When the end of the countdown is reached and auto-repeat is turned off, the alarm
sounds for 10 seconds or until you stop it by pressing any button. The countdown
time is automatically reset to its starting value after the alarm stops.
x When auto-repeat is turned on, the countdown will restart automatically without
pausing when it reaches zero. The alarm sounds in order to signal when the
countdown reaches zero.
x The countdown timer measurement operation continues even if you exit the Timer
Mode.
x Press D while a countdown operation is in progress to pause it. Press D again to
resume the countdown.
x To completely stop a countdown operation, first pause it (by pressing D), and
then press A. This returns the countdown time to its starting value.
EN-18
Timer
You can set the countdown timer within a range of
one minute to 24 hours. An alarm sounds when the
countdown reaches zero.
x You can also select auto-repeat, which automatically
restarts the countdown from the original value you set
whenever zero is reached.
x All of the operations in this section are performed in the
Timer Mode, which you can enter using C (page EN-8).
Timekeeping Mode time
Seconds
Hours Minutes
EN-17
To measure times with the stopwatch
Elapsed Time
D
D D D A
Start Stop Resume Stop Reset
Split Time
D
A A D A
Start Split
(SPL displayed)
Split release Stop Reset
Two Finishes
D
A D A A
Start Split
First runner
finishes.
Display time of
first runner.
Stop
Second runner
finishes.
Split release
Display time of
second runner.
Reset
EN-16
Stopwatch
The stopwatch lets you measure elapsed time, split
times, and two finishes.
x The display range of the stopwatch is 23 hours,
59minutes, 59.99 seconds.
x The stopwatch continues to run, restarting from zero
after it reaches its limit, until you stop it.
x An ongoing elapsed time measurement operation will
continue internally even if you change to another mode.
However, if you exit the Stopwatch Mode while a split
time is displayed, the split time will not be displayed
when you return to the Stopwatch Mode.
x All of the operations in this section are performed in
the Stopwatch Mode, which you enter by pressing C
(page EN-8).
1/100 second
Seconds
Hours Minutes
EN-15
To toggle between 12-hour and 24-hour timekeeping
In the Timekeeping Mode, press D to toggle between 12-hour timekeeping and
24-hour timekeeping.
x With 12-hour format, a P (PM) indicator is displayed near the hour digits between
the hours of noon to 11:59 p.m.
x With the 24-hour format, times are displayed in the range of 0:00 to 23:59, without
any indicator.
x The 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is
applied in all other modes.
x The P indicator is not displayed with the Timekeeping Mode time on the Timer
Mode and Dual Time Mode screens.
EN-14
To toggle the Timekeeping Mode time between DST and Standard Time
1. In the Timekeeping Mode, hold down A until the
seconds start to flash, which indicates the setting
screen.
2. Press C once to display the DST setting screen.
3. Press D to toggle between Daylight Saving Time (On
displayed) and Standard Time (OF displayed).
4. Press A twice to exit the setting screen.
x The DST indicator appears on the Timekeeping and
Alarm Mode screens to indicate that Daylight Saving
Time is turned on.
DST indicator
On/Off status
EN-13
4. Press A twice to exit the setting screen.
x The first press of A displays the UTC differential setting screen. Pressing A
again exits the setting screen.
x See “Daylight Saving Time (DST) Setting” below for details about the DST
setting.
x The day of the week is displayed automatically in accordance with the date
(year, month, and day) settings.
Daylight Saving Time (DST) Setting
Daylight Saving Time (summer time) advances the time setting by one hour from
Standard Time. Remember that not all countries or even local areas use Daylight
Saving Time.
EN-12
3. When the setting you want to change is flashing, use B and D to change it as
described below.
Screen To do this: Do this:
Reset the second to 00
Press D.
Toggle between Daylight Saving Time (On) and
Standard Time (OF)
Press D.
Change the hour or minute
Use B (–) and D (+).
Change the year
Change the month or day
EN-11
To set the time and date
1. In the Timekeeping Mode, hold down A until the
second starts to flash, which indicates the setting
screen.
2. Press C to move the flashing in the sequence shown
below to select the other settings.
Second
MinuteHourDST
Day YearMonth
CC
CC
CC
C
EN-10
Timekeeping
Use the Timekeeping Mode to set and view the current
time and date.
Month – Day
PM indicator
Second
Hour : Minute
Day of week
Operation Guide 3580
EN-29
To select the operation of Alarm 1
1. In the Alarm Mode, use D to select Alarm 1.
2. Press A to cycle through the available settings in the sequence shown below.
ALM
Alarm on Alarm off
AA
SNZ
ALM
Snooze
feature on
A
x The applicable alarm on indicator (SNZ and ALM) is displayed in all modes when
an alarm is turned on.
x SNZ indicator flashes during the 5-minute intervals between alarms.
x Displaying the Alarm 1 setting screen (page EN-24) while the snooze alarm is
turned on automatically turns off the snooze feature.
EN-28
Alarm on indicator Hourly time signal
on indicator
EN-27
To test the alarm
In the Alarm Mode, hold down D to sound the alarm.
To turn Alarms 2 and 3, and the Hourly Time Signal on and off
1. In the Alarm Mode, use D to select alarm number 2 or 3, or the Hourly Time
Signal.
2. Press A to toggle it on and off.
x Turning on alarm 2 or 3 displays the alarm on indicator.
x Turning on the Hourly Time Signal displays the hourly time signal on indicator.
x The alarm on (ALM) indicator and hourly time signal on (SIG) indicator are
displayed in all modes.
EN-26
5. Press A to exit the setting screen.
Alarm Operation
The alarm tone sounds at the preset time for 10 seconds, regardless of the mode
the watch is in. While the snooze function is turned on, the alarm operation will
repeat every five minutes up to seven times, or until the alarm or snooze function
is turned off.
x To stop the alarm tone after it starts to sound, press any button.
x Performing any one of the operations below during a 5-minute interval between
snooze alarms cancels the current snooze alarm operation.
Displaying the Timekeeping Mode setting screen (page EN-11)
Displaying the alarm 1 setting screen (page EN-24)
EN-25
3. Press C to move the flashing in the sequence shown below to select other
settings.
C
Hour DayMonth
C C
Minute
C
4. While a setting is flashing, use B (–) and D (+) to change it.
x To set an alarm that does not include a month (daily alarm, monthly alarm), set
for the month. Use B and D until the mark appears (between 12 and 1)
while month setting is flashing.
x To set an alarm that does not include a day (daily alarm, 1-month alarm), set
for the day. Use B and D until the
mark appears (between the end of the
month and 1) while the day setting is flashing.
x When setting the alarm time using the 12-hour format, take care to set the time
correctly as a.m. or p.m. (P indicator).
EN-24
To set an alarm time
1. In the Alarm Mode, use D to scroll through the alarm
screens until the one whose time you want to set is
displayed.
-1
:00
-2
-3
DD
DD
x Alarm 1 has a snooze feature.
x The snooze alarm operation repeats every five
minutes.
2. After you select an alarm, hold down A until the hour setting of the alarm time
starts to flash, which indicates the setting screen.
x This operation automatically turns on the alarm.
EN-23
Alarm Types
The alarm type is determined by the settings you make, as described below.
x Daily alarm
Set the hour and minutes for the alarm time. This type of setting causes the alarm
to sound everyday at the time you set.
x Date alarm
Set the month, day, hour and minutes for the alarm time. This type of setting
causes the alarm to sound at the specific time, on the specific date you set.
x 1-Month alarm
Set the month, hour and minutes for the alarm time. This type of setting causes the
alarm to sound everyday at time you set, only during the month you set.
x Monthly alarm
Set the day, hour and minutes for the alarm time. This type of setting causes the
alarm to sound every month at the time you set, on the day you set.
EN-22
Alarm
You can set up to three independent multi-function
alarms with hour, minutes, month, and day. When an
alarm is turned on, the alarm tone sounds when the alarm
time is reached. One of the alarms has a snooze feature.
You can also turn on an Hourly Time Signal that causes
the watch to beep every hour on the hour.
x There are three alarms numbered 1 through 3. The
Hourly Time Signal screen is indicated by :00.
x All of the operations in this section are performed in
the Alarm Mode, which you enter by pressing C (page
EN-9).
Alarm date
(Month – Day)
Alarm time
(Hour : Minute)
Alarm number
EN-21
3. While a setting is flashing, use B and D to change it as described below.
Screen To do this: Do this:
Change the hours or minutes
Use B (–) and D (+).
Toggle auto-repeat on (On) and off (OF)
Press D.
x To specify a countdown start time of 24 hours, set 0:00.
4. Press A to exit the setting screen.
x The auto-repeat on indicator ( ) is displayed on the Timer Mode screen while
this function is turned on.
x Frequent use of auto-repeat and the alarm can run down battery power.
EN-20
To set up the timer
1. While the countdown start time is on the display in the
Timer Mode, hold down A until the hour setting of the
countdown start time starts to flash, which indicates
the setting screen.
x If the countdown start time is not displayed, use the
procedure under “To use the timer” to display it.
2. Press C to move the flashing in the sequence shown
below to select other settings.
CCC
Hours Auto-repeatMinutes
Operation Guide 3580
EN-39
Timer:
Measuring unit: 1 second
Input range: 1 minute to 24 hours (1-minute increments and 1-hour increments)
Time up alert duration: 10 seconds
Other: Auto-repeat timing
Alarm: 3 Multi-function* alarms (1 with snooze feature);
Hourly Time Signal
* Alarm type: Daily alarm, Date alarm, 1-month alarm, Monthly alarm
Alert duration: 10 seconds
Dual Time: Hour, minutes, seconds, a.m./p.m. (P)
Other: Daylight Saving Time (summer time)/Standard Time
Illumination: LED (light-emitting diode); selectable illumination duration
(approximately 1.5 seconds or 3 seconds)
Other: Button operation tone on/off
EN-38
Specifications
Accuracy at normal temperature: ±30 seconds a month
Timekeeping: Hour, minutes, seconds, a.m./p.m. (P), month, day, day of the week
Time format: 12-hour and 24-hour
Calendar system: Full Auto-calendar pre-programmed from the year 2000 to
2099
Other: Daylight Saving Time (summer time)/Standard Time
Stopwatch:
Measuring unit: 1/100 second
Measuring capacity: 23:59'59.99"
Measuring modes: Elapsed time, split time, two finishes
EN-37
Timekeeping
x Resetting the seconds to 00 while the current count is in the range of 30 to 59
causes the minutes to be increased by 1. In the range of 00 to 29, the seconds are
reset to 00 without changing the minutes.
x The year can be set in the range of 2000 to 2099.
x The watch’s built-in full automatic calendar makes allowances for different month
lengths and leap years. Once you set the date, there should be no reason to
change it except after you have the watch’s battery replaced.
Illumination Precautions
x Illumination may be difficult to see when viewed under direct sunlight.
x Illumination turns off automatically whenever an alarm sounds.
x Frequent use of illumination runs down the battery.
EN-36
To turn the button operation tone on and off
In any mode (except when a setting screen is on the display), hold down C to
toggle the button operation tone on (
not displayed) and off ( displayed).
x Holding down C to turn the button operation tone on or off also causes the
watch’s current mode to change.
x The indicator is displayed in all modes when the button operation tone is turned
off.
Auto Return Features
x If you leave a screen with flashing digits on the display for two or three minutes
without performing any operation, the watch automatically exits the setting screen.
x If you leave the watch in the Alarm Mode for two or three minutes without
performing any operation, it automatically changes to the Timekeeping Mode.
Scrolling
The B and D buttons are used in various modes and setting screens to scroll
through data on the display. In most cases, holding down these buttons during a
scroll operation scrolls through the data at high speed.
EN-35
Reference
This section contains more detailed and technical information about watch
operation. It also contains important precautions and notes about the various
features and functions of this watch.
Button Operation Tone
The button operation tone sounds any time you press one
of the watch’s buttons. You can turn the button operation
tone on or off as desired.
x Even if you turn off the button operation tone, the alarm,
Hourly Time Signal, and Timer Mode alarm all operate
normally.
EN-34
To specify the illumination duration
1. In the Timekeeping Mode, hold down A until the
seconds start to flash, which indicates the setting
screen.
2. While the seconds are flashing, press B to toggle
the illumination duration between 1.5seconds (
) and
3seconds (
).
3. Press A twice to exit the setting screen.
EN-33
Illumination
The watch has an LED light that you can turn on for reading in the dark.
x See “Illumination Precautions” (page EN-37) for more important information.
To illuminate the display
In any mode, press B to turn on illumination.
x You can use the procedure below to select either 1.5 seconds or 3 seconds as the
illumination duration. When you press B, the illumination will remain on for about
1.5 seconds or 3 seconds, depending on the current illumination duration setting.
EN-32
4. When the setting you want to change is flashing, use B and D to change it as
described below.
Screen To do this: Do this:
Toggle between Daylight Saving Time (On) and
Standard Time (OF)
Press D.
Change the hour or minute
Use B (–) and D (+).
5. Press A to exit the setting screen.
x The DST indicator on the Dual Time Mode screen indicates that DST is turned
on for the Dual Time Mode time.
EN-31
To set the Dual Time
1. Press C to enter the Dual Time Mode (page EN-9).
2. In the Dual Time Mode, hold down A until the DST
setting starts to flash, which indicates the setting
screen.
3. Press C to move the flashing in the sequence shown
below to select the other settings.
CCC
DST MinuteHour
Dual time
(Hour : Minute)
DST indicator
Timekeeping Mode time
EN-30
Dual Time
The Dual Time Mode lets you keep track of time in a different time zone. You can
select Standard Time or Daylight Saving Time for the Dual Time Mode time.
x In the Dual Time Mode, the seconds count is synchronized with the seconds count
of the Timekeeping Mode.
Operation Guide 3580
EN-40
Battery:
One lithium battery (Type: CR2032)
Battery nominal voltage: 3V
Approximately 10 years on type CR2032 (assuming alarm operation 10 sec./day
and one illumination operation 1.5 sec./day)
Frequent illumination shortens the battery life.
Specifications are subject to change without notice.
