YCL-6 makes the full use of the single-chip resources which is featured with the function of alarm clock, countdown clock, stopwatch and counter.
The circuit is mainly composed by the single-chip circuit, display circuit, keyboard input, signal ringing circuit and power circuit.
1. Single-chip circuit: It’s based on AT89C2051 which including the Power-on Reset and clock circuit.
2. Display Circuit: The main component is 2-bit digital tube in red. The driver uses the PNP transistor and it’s equipped with current-limiting resistance at every port. It’s with scanning-driven way and uses P1.0~P1.6. The colon part use four pieces of diode in Φ3 red with scanning-driven way. And it uses P1.7.
3. keyboard input: The key S1~S3 are with reused function which reused with the display part of P3.5,P3.4 and P3.2. And here is the operating principle.
Output high level at the related PIN to read out the status of keys and debounce via single-chip system to give the keys with corresponding value.
4. Signal Ringing circuit: It’s composed by buzzer and PNP transistor. And the operating principle is that the buzzer will send sound in fixed frequency after the PNP transistor turns on. It’s with independent port-driven way and uses P3.7. J1 is used for connecting the extrocontrol equipments which will output the low level when there is no ringing signal, or high level with ringing signal.
5. Power Circuit: It’s composed by three terminal integrated circuit which will supply the whole system with the stable voltage.
1 x C51 6 Bits Digital Electronic Clock Electronic Production Suite DIY Kits