79 Asynchronous 3-Bit Down Counter

79 : Asynchronous 3-Bit Down Counter

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  • 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

#InputOutput
0clocksegment a - OUT0
1resetsegment b - OUT1
2I0 - Inputsegment c - OUT2
3I1 - Nonesegment d - OUT3
4I2 - Nonesegment e - OUT4
5I3 - Nonesegment f - OUT5
6I4 - Nonesegment g - OUT6
7dot - None