Restart button in counter 0-9

[ryan.x]

how can restart my counter 0-9 in any time
74ls90 and ic555

 

[gophert]

Either pin combination in the inputs below to get low values on all outputs. Datasheets are your friend, every chip has one.

https://www.ti.com/lit/ds/symlink/sn54ls90.pdf?ts=1612880471091&ref_url=https%253A%252F%252Fwww.google.com%252F

 

[ryan.x]

Either pin combination in the inputs below to get low values on all outputs. Datasheets are your friend, every chip has one.

yes, but i want to return it to zero in any time
example: when start count from 0, 1, 2, and you push a button to start from beginning

 

[gophert]

yes, but you just need to connect your button to the right pin. The right pin depends on how you connect the inputs to achieve the Count mode. How are your four inputs connected? Circle the version you are usin the truth able I posed above.

 

[ryan.x]

This is my circle
i want button to restart my circuit from beginning like what i say to you in example

 

[eTech]

This is my circle
i want button to restart my circuit from beginning like what i say to you in exampleView attachment 129656

Connect 7490 pins 2,3,6,7 to ground.
The counter will count from 0...9,0...9,0...9,0..etc.

 

[eTech]

Add a reset button:

Edit: R2 should be 220 ohms.

 

[rjenkinsgb]

I believe the R9 inputs should stay grounded; they override the reset 0, according to the truth table.

 

[gophert]

 

[eTech]

Corrected schematic in post #7

 

[ryan.x]

my schematic #5 is correct, when i run my circle its auto start count from 0 to 9 and restart from 0 , but i want to rest in middle of count

 

[AnalogKid]

In the #7 circuit, if C6 is there for switch debouncing, it is not needed. The counter is held in Reset as long as the switch is pressed, and comes out of reset only after release. This means that you do not need any debouncing, since trailing edge bounce is so brief that it will look the same as a clean button release. Plus, a debounce period of less than 100 us isn't very effective.

Thus, delete C6.

If C6 is there as a power-on reset, then forget all of that.

BUT ...

Revisit R2. To hold two standard TTL (post #5) inputs below a logical low voltage threshold requires 500 ohms or less *per input*. This puts the max R1 value at approx 220 ohms (for 12% margin).

ak

 

[ChrisP58]

how can restart my counter 0-9 in any time
74ls90 and ic555

The answers above are to (manually) reset the counter at any time (you press the button.)

Did you meant to say: How can I automatically rest my counter to 0 when it reaches X?

To do so, you need to add logic gates connected to the four outputs of the counter to generate a reset pulse when the states of the four outputs equal the value at which you want to reset the counter.

 

[AnalogKid]

push a button to start from beginning

ak