# Mod-10 Counter

Discussion in 'Homework Help' started by num4ir, May 4, 2009.

1. ### num4ir Thread Starter New Member

May 4, 2009
3
0
I'm trying to construct a mod-10 counter but im stumbled, i did the best i can do but im afraid im missing or gates to make it a mod-10 im completely stumbled. I'm using t-ff's I'd appreciate it if someone could help me out

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2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
282
One way to get a modulo-10 counter is to watch the state of the flip-flops with external logic, so the next clock after the count of 9 sets the counter state back to 0.

Another is like the 7490, with a divide by 2 stage, and three flip-flops that short count back to 0 after reaching 5.

3. ### num4ir Thread Starter New Member

May 4, 2009
3
0
i'm not the brightest in this situation i appreciate the post but i still dont understand how to turn this mod-16 into a mod 10...i understand it counts to 0-15 which is 1111..i dont know

4. ### StayatHomeElectronics Well-Known Member

Sep 25, 2008
864
40
what beenthere suggested first was simply look when the mod-16 counter gets to the number 9, or 1001, and then force the counter to go back to 0000. You have a RESET pin on each of your FF that will change the output to zero, most likely at the next clock.

0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 0000, ....

What logic can be used to detect the single state equal to 9?

5. ### num4ir Thread Starter New Member

May 4, 2009
3
0
add an OR gate to fix q3 and q1?

6. ### StayatHomeElectronics Well-Known Member

Sep 25, 2008
864
40
Why do you say q1 and q3? How about q0 and q3?

Also, if you use an OR then anytime a 1 get placed in the output of either position you are looking at a RESET would be triggered. You want both conditions to be true, AND.