aladeenb / digital-chess-timer

Simulation of a chess timer using Logisim

Digital Integrated Circuits Project 2021/2022

Digital Chess Timer

Description

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.

Block Schematic

Electrical Schematic

7-Seg IC

Clock IC

The Digital Chess Timer

Electrical Characteristics

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

Operation Mode

	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

Functioning

Clock Logic

• 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.

Timer Logic 7-seg Display

Reset Logic

Moving to the next state by passing only one pulse. Must push on 0 first.

Stop/Start Logic

Stop/Start

When Stop/Start pin is set to 0, Clock gate get supplied by voltage, hence clock pulses are blocked.

Start

When Stop/Start pin is set to 1, Clock gate get supplied by null voltage, hence activation of one of the timers.

Surrender Logic

When surrender pin is set to 1, Clock gate is supplied by voltage, hence clock pulses are blocked.

Bill of Materials

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

Bibliography

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/

Ala Eddine BATTIKH | UPB FILS