79 Asynchronous 3-Bit Down Counter
79 : Asynchronous 3-Bit Down Counter
- Author: Dikshant, Mohit, Sanidhya
- Description: This Project works as a down counter which counts from 7 to 0
- GitHub repository
- Clock: 0 Hz
How it works
See The Wokwi gate and simulation.
- The sequence in which the counter works is as follows : 7: 0111 3: 0011 5: 0101 1: 0001 6: 0110 2: 0010 4: 0100 0: 0000 Here's how the counter works : first, all the three flip flops are set to 1 then for changing the inputs i have used the switch 1 of the Dip switch.
- When the count signal is triggered, the first flip-flop (least significant bit) toggles from 1 to 0, which produces the binary number 0111 (decimal 7).
- The second count signal should not trigger a change in the counter value, as the next count is 3, not 6.
- The third count signal triggers a change in the counter value, where the second flip-flop toggles from 1 to 0, which produces the binary number 0101 (decimal 5).
- The fourth count signal should not trigger a change in the counter value, as the next count is 1, not 4.
- The fifth count signal triggers a change in the counter value, where the first flip-flop toggles from 0 to 1, and the third flip-flop toggles from 0 to 1, which produces the binary number 0110 (decimal 6).
- The sixth count signal should not trigger a change in the counter value, as the next count is 2, not 5.
- The seventh count signal triggers a change in the counter value, where the second flip-flop toggles from 0 to 1, which produces the binary number 0100 (decimal 4).
- The eighth count signal triggers a change in the counter value, where all three flip-flops toggle from 0 to 1, which produces the binary number 0000 (decimal 0).
- The counter stays at 000 until the count signal is triggered again, which causes all three flip-flops to be set back to 1, and the counting process starts again from the beginning of the sequence. In summary, the 3-bit asynchronous down counter counts down in the sequence 7, 3, 5, 1, 6, 2, 4, 0 using three flip-flops and asynchronous inputs to trigger each flip-flop in the sequence.
How to test
For Testing this project, the user has to use the switch 1 of the dip switch to give different inputs and then get the desired output on the 7-segment display.
IO
| # | Input | Output |
|---|---|---|
| 0 | clock | segment a - OUT0 |
| 1 | reset | segment b - OUT1 |
| 2 | I0 - Input | segment c - OUT2 |
| 3 | I1 - None | segment d - OUT3 |
| 4 | I2 - None | segment e - OUT4 |
| 5 | I3 - None | segment f - OUT5 |
| 6 | I4 - None | segment g - OUT6 |
| 7 | dot - None |