Application and function descriptionApplication and function description
Function description
This IC can analyze the DCF77 signal, which is received by a receiver and demodulated. Thereceived time and date can output directly to a 7-segment
displays. The clock synchronizes itself automatically once a day. The hour of the synchronization can be set in the menu.
The time is displayed according to DIN 5008, which means a leading 0 at the hour. 8 a.m. looks like 08:00:00 and 8 p.m. 20:00:00
Due to the 6-digit display, the date is not shown according to DIN 5008. The 24 December 2020 looks on the display like 24.12.20.
The DCF77 signal is a low frequency radio signal which transferred the time and date. It will besent in Frankfurt am Main, derived of the local atomic
clock and sent with the carrier frequencyof 77.5 kHz. Therefore, these watches are also known as radio clock.
The input for the DCF77 antenna can now automatically detect whether a pullup resistor isrequired and whether the input has to be inverted.
Even a simple alarm function is implemented.
This IC has the standard OnChip display technology and is suitable for small displays. These can be connected directly to the IC and require only 6
additional resistors.
This IC also has an adjustable brightness control for the display, thereby the display is easy toread during the day and at night it does not light out the
entire room.
With this IC the temperature will be displayed alternately with the time and or date.
This IC has a bootloader, which allows you to update the IC firmware.This means that you will always remain at the current state of the Firmware for
the IC, without further costs.
Alarm Function
The simple alarm clock function allows you to set one alarm time so that you are wake up every morning.
In the menu the alarm and the snooze time can be set. With the adjusted snooze time the alarm waits if the alarm is not stopped at a wake-up call, but
the snooze function is activated. The maximumalarm time can be adjusted between 2 and 60 minutes.
The alarm can be activated and deactivated also outside the menu.If the wake-up call is active with S1 or S2 the alarm clock can be stopped and with
S3 or S4 the snooze function will be activated.
NOTICE
Dissembled time
Because the DCF clock daily synchronized with the current DCF time, it is possible that in worst cases, an incorrect time is read and therefore the
wake-up call comes at a wrong time! Therefore, the time synchronization should eventually be placed in a time of day where it is possible to check
the correct time before sleeping, if the alarm function is used.
Technical data
Operating voltage: 9 - 12 volts DC
Current: 100mA
Power: approximately 0.9 W (at 9 volts)
Volume level of the buzzer: approx. 85 DB
Accuracy of the timer: better uncalibrated 99.9 %; calibrated better 99.999 %
Temperature accuracy:
Worst inaccuracy: ±2.5 °C
Typical: ±1 °C
Calibrated: <±1 °C
The values apply when using the LM35, when calibrated, the value can also be reached for other sensors.
