The image below shows the circuit of the stopwatch. It consists of a 7-segment connected to Atmega32 using multiplexed technique. A 7447 Decoder was used to control the numbers displayed on the 6 digits of the 7-segment. and three push buttons were connected to generate interrupts to pause, resume and reset the stopwatch!
- ATmega32 Microcontroller with frequency 1Mhz.
- Timer1 in ATmega32 set to CTC mode.
- six Common Anode 7-segments.
- 7447 decoder 4-pins connected to the first 4-pins in PORTC.
- First 6-pins in PORTA as the enable/disable pins for the six 7-segments.
- To stop the watch External Interrupt INT0 with falling edge is generated by push button with the internal pull-up resistor.
- To pause the watch External Interrupt INT1 with raising edge is generated by a push button with the external pull-down resistor.
- To reser the watch External Interrupt INT2 with falling edge is generated by a push button with the internal pull-up resistor.
That's All. Hope you found this useful. Thank you for reading :)