19 votes 19 votes The number of flip-flops required to construct a binary modulo $N$ counter is __________ Digital Logic gate1994 digital-logic sequential-circuit flip-flop digital-counter fill-in-the-blanks + – Kathleen asked Oct 4, 2014 • recategorized Apr 25, 2021 by Lakshman Bhaiya Kathleen 6.3k views answer comment Share Follow See 1 comment See all 1 1 comment reply Nitesh Singh 2 commented Dec 29, 2018 reply Follow Share binary modulo n counter means Asynchronous mod n up/down counter. 0 votes 0 votes Please log in or register to add a comment.
Best answer 33 votes 33 votes Let say we have to design a mod-$8$ counter i.e $000$ to $111$. So we need $3$ bits to represent i.e $3$ FF. For mod $N: 2^x = N$ $\implies x = \left \lceil (\log_2N) \right \rceil $ Praveen Saini answered Feb 27, 2015 • edited Apr 23, 2021 by Lakshman Bhaiya Praveen Saini comment Share Follow See all 10 Comments See all 10 10 Comments reply mcjoshi commented Sep 6, 2016 reply Follow Share I have a doubt: if it is possible to form mod 8 counter using 3 FF. Why do we use Ring Counter or Johnson counter? 7 votes 7 votes junk_mayavi commented Nov 14, 2017 reply Follow Share to make mod8 ring counter, we will need 8 FFs. 3 votes 3 votes Niraj Singh 2 commented Dec 13, 2017 reply Follow Share this is for asynchronous counter 0 votes 0 votes tusharp commented Dec 11, 2018 reply Follow Share Counter Flip flops Counting Ring N mod(N) Johnson N mod(2N) Asynchronous N mod(2^N) I think here type of counter should be explicitly mentioned to find number of flip flops. @Shaik Masthan 6 votes 6 votes Shaik Masthan commented Dec 11, 2018 reply Follow Share actually, the counting sequence is not in order for Ring or Johnson ===> we can't use them for requirement of the question ! the one and only choice is Go with asynchronous counter ===> ⌈log$_2$n ⌉ 3 votes 3 votes soumayan bandhu commented Jan 30, 2019 reply Follow Share @Shaik Masthan for ring counter and johnson's counter is the output of left flipflop is MSB? And also please mention which is the MSB for asynchronous UP and down counter. 0 votes 0 votes Shaik Masthan commented Jan 30, 2019 reply Follow Share in GATE exam, they will specify which is LSB and which is MSB 3 votes 3 votes Doraemon commented May 10, 2020 reply Follow Share @Shaik Masthan Sir. According to me we can also construct a synchronous binary mod N counter. and it will have ceil(logn ) counters. Counters can have any sequence of states. And here binary mod N counters means that it follows binary sequence like (0-1-2-3-4..... upto 2^n-1 )and then this cycle repeats. According to Morris Mano "A counter that follows binary sequence is called binary counters" Am I correct? 0 votes 0 votes Abir Mazumder commented Sep 22, 2020 reply Follow Share A simple mod N counter that counts from 0 to N-1 , so either you use a synchronous or asynchronous approach , you will be needing LogN FF . The only difference will be the amount of additional circuitry that will be needed in case of a synchronous counter. 1 votes 1 votes Abhrajyoti00 commented Jan 6, 2023 reply Follow Share To construct a binary modulo $N$ counter, we need to store the current count in the counter. The number of bits needed to store a number in binary is equal to $log_2(N)$, where $N$ is the maximum number that can be stored. 0 votes 0 votes Please log in or register to add a comment.