Q- Design a circuit to transfer data serially from one shift register to other. Ans: If we have a N-bit shift register then we need only N clock cycles to shift those N-bits to the other register. If we apply more or less than this many clock cycles then our operation of shifting would not […]
Sequential Circuits
Johnson Counter
While Ring counter, we have connected Q of last to D of 1st FF, but in Johnson Counter we connect Q bar of last to D of 1st FF as shown below and we also don’t need to connect preset of 1st FF. This is also called Twisted Ring counter: And JK implementation is as follow: And we have […]
Ring counter
This is a special type of register in which 1 moves in the output in the ring i.e. initially output of 1st FF is 1. On next edge this 1 is transferred to output of 2nd FF while previous output becomes 0. Similarly on next clock output of 3rd FF becomes 1. Similarly it continuous till last FF […]
Shift register
In this type of register value stored in the register can be either shifted to left or right depending upon the circuit as: PARALLEL IN PARALLEL OUT: This type of shift registers is already discussed above. SERIAL IN SERIAL OUT: Right shift: Here data is shifted by one bit from left to right with every clock […]
Registers
A register is a group of 1- bit memory cells. To make a N-bit register we need N 1-bit memory cells. Register with parallel load: We can represent a simple 4-bit register as: We can give the values to be stored at input and we get that value stored at the next clock pulse. But […]
Flip flop = 1 bit Memory
1-bit Memory Cell: We know that flip-flop can store either zero or one permanently until a change is made in the inputs. Hence flip-flop would work as 1-bit memory cell.
Conversion: Generic
CONVERSION OF ONE FLIP-FLOP TO OTHER: As we have already seen from the way we derived D flip-flop from RS flip-flop or the way we derived T flip-flop from JK flip-flop or the way we derived JK flip-flop from RS flip-flop by feeding back outputs that to derive a flip-flop from the other flip-flop we need to design a combinational arrangement […]
Conversion: D to T & T to D FF
Similar to previous conversions, we get the circuits as follow: D FF to T FF: T FF to D FF: Note: We have not shown the clock but we can attach the clock signal to the given FF. Similarly we can obtain other conversions.
Conversion: D to RS flip-flop
We first write the truth table for required Flip-flop i.e. RS FF Now we write the excitation table of given FF i.e. D flip-flop as Now we combine two tables to get the combinational circuit as: Now we design the combinational circuit to convert J, K to corresponding R, S K-map for D input: And […]
Conversion: RS to JK flip-flop
We first write the truth table for required Flip-flop i.e. JK FF Now we write the excitation table of given FF SR flip-flop as Now we combine two tables to get the combinational circuit as: Now we design the combinational circuit to convert J, K to corresponding R, S K-map for S input: K-map for […]