What Would A Bidirectional Register Be Used For

Flip flops tin can exist used to store a unmarried fleck of binary data (1or 0). Nevertheless, in order to store multiple $.25 of data, we demand multiple flip flops. N flip flops are to be connected in an lodge to store n bits of data. A Register is a device which is used to shop such data. Information technology is a group of flip flops connected in serial used to store multiple bits of data.

The information stored within these registers can be transferred with the help of shift registers. Shift Register is a group of flip flops used to store multiple bits of data. The bits stored in such registers tin can be made to move within the registers and in/out of the registers past applying clock pulses. An n-bit shift register can exist formed past connecting north flip-flops where each flip flop stores a single fleck of data.
The registers which volition shift the bits to left are called "Shift left registers".
The registers which will shift the bits to right are called "Shift right registers".

Shift registers are basically of 4 types. These are:

Series In Series Out shift register
Serial In parallel Out shift register
Parallel In Serial Out shift register
Parallel In parallel Out shift annals

Serial-In Serial-Out Shift Register (SISO) –

The shift register, which allows series input (one bit after the other through a single data line) and produces a series output is known as Serial-In Serial-Out shift register. Since there is only one output, the data leaves the shift register one bit at a time in a serial pattern, thus the proper name Serial-In Serial-Out Shift Annals.

The logic circuit given beneath shows a serial-in serial-out shift register. The circuit consists of four D flip-flops which are connected in a series fashion. All these flip-flops are synchronous with each other since the aforementioned clock signal is applied to each flip flop.

The above circuit is an example of shift right register, taking the serial data input from the left side of the flip bomb. The main utilize of a SISO is to act equally a delay chemical element.

Series-In Parallel-Out shift Annals (SIPO) –

The shift register, which allows serial input (1 flake afterwards the other through a single information line) and produces a parallel output is known as Series-In Parallel-Out shift register.

The logic excursion given below shows a series-in-parallel-out shift register. The excursion consists of four D flip-flops which are connected. The articulate (CLR) betoken is connected in addition to the clock bespeak to all the 4 flip flops in order to RESET them. The output of the commencement flip bomb is connected to the input of the next flip flop and so on. All these flip-flops are synchronous with each other since the same clock betoken is applied to each flip bomb.

The above circuit is an instance of shift right annals, taking the serial data input from the left side of the flip bomb and producing a parallel output. They are used in communication lines where demultiplexing of a data line into several parallel lines is required because the main utilize of the SIPO register is to catechumen serial information into parallel data.

Parallel-In Series-Out Shift Register (PISO) –

The shift annals, which allows parallel input (information is given separately to each flip flop and in a simultaneous manner) and produces a serial output is known as Parallel-In Series-Out shift register.

The logic circuit given below shows a parallel-in-serial-out shift register. The excursion consists of iv D flip-flops which are connected. The clock input is direct connected to all the flip flops only the input data is continued individually to each flip flop through a multiplexer at the input of every flip flop. The output of the previous flip flop and parallel data input are connected to the input of the MUX and the output of MUX is continued to the next flip flop. All these flip-flops are synchronous with each other since the same clock point is applied to each flip flop.

A Parallel in Serial out (PISO) shift register us used to convert parallel information to serial information.

Parallel-In Parallel-Out Shift Register (PIPO) –

The shift register, which allows parallel input (information is given separately to each flip flop and in a simultaneous manner) and besides produces a parallel output is known equally Parallel-In parallel-Out shift register.

The logic circuit given below shows a parallel-in-parallel-out shift register. The circuit consists of four D flip-flops which are continued. The clear (CLR) signal and clock signals are connected to all the four flip flops. In this blazon of register, at that place are no interconnections between the individual flip-flops since no serial shifting of the data is required. Information is given as input separately for each flip bomb and in the aforementioned way, output also collected individually from each flip flop.

A Parallel in Parallel out (PIPO) shift register is used as a temporary storage device and like SISO Shift register it acts equally a delay element.

Bidirectional Shift Annals –

If we shift a binary number to the left by one position, it is equivalent to multiplying the number past ii and if we shift a binary number to the right by one position, it is equivalent to dividing the number by ii.To perform these operations we need a register which can shift the data in either direction.

Bidirectional shift registers are the registers which are capable of shifting the data either correct or left depending on the way selected. If the manner selected is 1(high), the information volition exist shifted towards the correct management and if the mode selected is 0(low), the data will be shifted towards the left direction.

The logic circuit given below shows a Bidirectional shift register. The circuit consists of 4 D flip-flops which are continued. The input data is continued at 2 ends of the circuit and depending on the mode selected just 1 and gate is in the agile state.

Shift Register Counter –

Shift Annals Counters are the shift registers in which the outputs are connected back to the inputs in social club to produce particular sequences. These are basically of 2 types:

Band Counter –
A ring counter is basically a shift register counter in which the output of the first flip flop is connected to the side by side flip flop so on and the output of the last flip flop is again fed back to the input of the first flip bomb, thus the name ring counter. The data pattern inside the shift register will broadcast as long every bit clock pulses are applied.

The logic excursion given below shows a Ring Counter. The circuit consists of four D flip-flops which are connected. Since the circuit consists of four flip flops the data pattern will repeat after every four clock pulses as shown in the truth table below:

A Ring counter is generally used considering it is self-decoding. No actress decoding excursion is needed to make up one's mind what land the counter is in.
Johnson Counter –
A Johnson counter is basically a shift register counter in which the output of the first flip flop is connected to the next flip bomb and so on and the inverted output of the last flip flop is again fed dorsum to the input of the first flip flop. They are too known every bit twisted ring counters.
The logic circuit given below shows a Johnson Counter. The circuit consists of 4 D flip-flops which are continued. An northward-stage Johnson counter yields a count sequence of 2n different states, thus also known as a mod-2n counter. Since the excursion consists of iv flip flops the data pattern will repeat every viii clock pulses equally shown in the truth table below:

The principal advantage of Johnson counter is that it but needs n number of flip-flops compared to the ring counter to circulate a given data to generate a sequence of 2n states.

Applications of shift Registers –

The shift registers are used for temporary data storage.
The shift registers are also used for data transfer and data manipulation.
The series-in serial-out and parallel-in parallel-out shift registers are used to produce time delay to digital circuits.
The serial-in parallel-out shift register is used to convert series data into parallel data thus they are used in communication lines where demultiplexing of a data line into several parallel line is required.
A Parallel in Series out shift register us used to convert parallel data to serial information.

Reference –
Registers – ee.usyd.edu.au