A digital clock designed for chess games. It mainly consists of two timers which cannot count at the same time. The source clock is alternatively transmitted between the two down counters using a switcher.
| Component | Specification |
|---|---|
| Power Supply | 9V Battery |
| Resistor | 68 Ω, for green LEDs |
| 56 Ω, for red LEDs | |
| Transistor | pMOS (MOSFET) |
| Splitter | |
| Button | |
| Switch | On/Off |
| 74HC32D | OR Gate IC |
| 74HC04 | NOT Gate IC |
| 74HC08 | AND Gate IC |
| 7-seg | LCD |
| 74HC93 | Flip-Flop |
| LED | Green |
| Red |
| Stop/Start | Next | Reset | 0 (zero) | Surrender | |
|---|---|---|---|---|---|
| Start the game | 1 | x | 0 | 0 | 0 |
| Stop the game | 0 | x | 0 | 0 | 0 |
| Resume the game | 1 | x | 0 | 0 | 0 |
| Bob’s turn | 1 | 0 | 0 | 0 | 0 |
| Alice’s turn | 1 | 1 | 0 | 0 | 0 |
| Surrender – Finish the game | x | x | x | x | 1 |
| Reset the timers | 1 | x | 1 | 1 | 0 |
- The main clock feeds both timers with pulses periodically.
- It is connected to the source of a P-Type Transistor.
- The pulses will be valid only if the gate is supplied with 0V (in other words, reset 0, 0 is 0, surrender is 0 and both counters are non-null). Timers will be off otherwise.
Moving to the next state by passing only one pulse. Must push on 0 first.
When Stop/Start pin is set to 0, Clock gate get supplied by voltage, hence clock pulses are blocked.
When Stop/Start pin is set to 1, Clock gate get supplied by null voltage, hence activation of one of the timers.
When surrender pin is set to 1, Clock gate is supplied by voltage, hence clock pulses are blocked.
| Component | Quantity | Specification |
|---|---|---|
| Power Supply | 1 | 9V Battery |
| Resistor | 2 | 68 Ω, for green LEDs |
| 56 Ω, for red LEDs | ||
| Transistor | 4 | pMOS (MOSFET) |
| Splitter | 4 | |
| Button | 4 | |
| Switch | 2 | On/Off |
| 74HC32D | 4 | OR Gate IC |
| 74HC04 | 21 | NOT Gate IC |
| 74HC08 | 20 | AND Gate IC |
| 7-seg | 8 | LCD |
| 74HC93 | 4 | Flip-Flop |
| LED | 2 | Green |
| 2 | Red |
https://sweetcode.io/logisim-software-digital-clock/ https://en.wikipedia.org/wiki/Chess_clock https://digitalgametechnology.com/products/chess-clocks/dgt2010-official-fide-chess-clock https://ro.farnell.com/
