[SOLVED] How can I set up a binary country to count in bcd?

[Zanderist]

How can I set up a binary counter to count in bcd?

https://pdf1.alldatasheet.com/datasheet-pdf/view/5723/MOTOROLA/SN74LS393D.html

I am trying to set up a a 4-bit binary counter to rest at count ten.

Since I didn't have LS390' I had to create a condition rest clock made from an AND gate chip.

First I used one gate to get triggered when Qc and Qa where active. However when I do this it only counts to seven and resets. Then I tried adding in the full rest conditions using three AND gates making a number ten detector ( hex inverter chip is used as well). It still continues to count to seven. However if I let the counter count with the number ten detector still connected but not to the reset I can see that the circuit turns high with an LED when the counter reaches number ten.

How would I go about setting up this chip to count in BCD, without having to get buy new chips?

 

[kripacharya]

Re: How can I set up a binary counter to count in bcd?

you have to AND Q3 and Q1 (out of Q0,Q1, Q2, Q3) and feed to the reset pin. Counter will count from 0 ..9. The 0xA will trigger a reset back to 0. So there will be a short glitch at count 10 which is the propagation delay of your AND gate and your '393 reset circuit.

 

[Zanderist]

Re: How can I set up a binary counter to count in bcd?

I was able to correct the propagation delay by using a small cap(104) connected from the output of the AND gate to ground.