S R Latch Notes
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Flip Flops-
*Sr Latch Notes Definition
*Sr Latch Notes Template
*Sr Latch Example
Before you go through this article, make sure that you have gone through the previous article on Flip Flops.
We have discussed-
*A Flip Flop is a memory element that is capable of storing one bit of information.
*It is also called as Bistable Multivibrator since it has two stable states either 0 or 1.
Whenever the clock signal is LOW, the inputs S and R are never going to affect the output. The clock has to be high for the inputs to get active. Thus, SR flip-flop is a controlled Bi-stable latch where the clock signal is the control signal. Again, this gets divided into positive edge triggered SR flip flop and negative edge triggered SR flip-flop. Thus, the output has two stable states based on the inputs which have been discussed below. #077 NOR Gate SR Latch. Set-Reset latch implemented with NOR gates. This circuit is another implementation of a Set-Reset flip-flop, this time using NOR gates. Sometimes this is referred to as a “NOR Latch”. A 74LS02 is used to provide the two NOR gates required. See the LEAP#061 SRLatch circuit for an implementation using BJTs. Lecture #11: Latches, Flops, and Metastability Paul Hartke Phartke@stanford.edu Stanford EE121 February 14, 2002 Administrivia. Make sure to fill out TA evaluations!!! – Incentive: 5 Point bonus on Lab 6. Lab 6 is only worth 60 – Everything is anonymous. Lab 6 Prelab is due Midnight on Thursday. Note that the internal latch inputs will both go from 1 to 0 if the S and R inputs are both 1 when the clock goes low. Hence we must never have S and R at 1 when the clock is 1. We make the following rules for changing inputs. ZDon’t change the inputs while the clock is asserted.
There are following 4 basic types of flip flops-
*SR Flip Flop
*JK Flip Flop
*D Flip Flop
*T Flip Flop
In this article, we will discuss about SR Flip Flop.SR Flip Flop-
*SR flip flop is the simplest type of flip flops.
*It stands for Set Reset flip flop.
*It is a clocked flip flop.Construction of SR Flip Flop-
There are following two methods for constructing a SR flip flop-
*By using NOR latch
*By using NAND latch1. Construction of SR Flip Flop By Using NOR Latch-
This method of constructing SR Flip Flop uses-
*NOR latch
*Two AND gatesLogic Circuit-
The logic circuit for SR Flip Flop constructed using NOR latch is as shown below-2. Construction of SR Flip Flop By Using NAND Latch-
This method of constructing SR Flip Flop uses-
*NAND latch
*Two NAND gatesLogic Circuit-
The logic circuit for SR Flip Flop constructed using NAND latch is as shown below-Logic Symbol-
The logic symbol for SR Flip Flop is as shown below-Truth Table-
Q casino and hotel california casino. The truth table for SR Flip Flop is as shown below-INPUTSOUTPUTSSRQn
(Present State)Qn+1
(Next State)000000110100011010011011110Indeterminate111IndeterminateTruth Table
The above truth table may be reduced as-INPUTSOUTPUTSREMARKSSRQn
(Present State)Qn+1
(Next State)States and Conditions00XQnHold State condition S = R = 001X0Reset state condition S = 0 , R = 110X1Set state condition S = 1 , R = 011XIndeterminateIndeterminate state condition S = R = 1Truth TableCharacteristic Equation-
Draw a k map using the above truth table-
From here-
Qn+1 = ( SR + SR’ ) ( Qn + Q’n ) + Qn ( S’R’ + SR’ )Qn+1 = S + QnR’Excitation Table-
The excitation table of any flip flop is drawn using its truth table.
What is excitation table?
For a given combination of present state Qn and next state Qn+1, excitation table tell the inputs required.QnQn+1SR000X0110100111X0Excitation Table
To gain better understanding about SR Flip Flop,
Next Article-JK Flip Flop
Get more notes and other study material of Digital Design.
Watch video lectures by visiting our YouTube channel LearnVidFun.SR Flip Flop | Diagram | Truth Table | Excitation TableDescriptionSr Latch Notes DefinitionSR flip flop is the simplest type of flip flops. SR Flip Flop Construction, Logic Circuit Diagram, Logic Symbol, Truth Table, Characteristic Equation & Excitation Table are discussed.AuthorGate VidyalayPublisher Logo
The JK Flip Flop is the most widely used flip flop. It is considered to be a universal flip-flop circuit. The sequential operation of the JK Flip Flop is the same as for the RS flip-flop with the same SET and RESET input.
The difference is that the JK Flip Flop does not the invalid input states of the RS Latch (when S and R are both 1). The JK Flip Flop name has been kept on the inventor name of the circuit known as Jack Kilby.
The basic symbol of the JK Flip Flop is shown below:
The basic NAND gate RS flip-flop suffers from two main problems.
*Firstly, the condition when S = 0 and R = 0 should be avoided.
*Secondly, if the state of S or R changes its state while the input which is enabled is high, the correct latching action does not occur.
Thus to overcome these two problems of the RS Flip-Flop, the JK Flip Flop was designed.
The JK Flip Flop is basically a gated RS flip flop with the addition of the clock input circuitry. When both the inputs S and R are equal to logic “1”, the invalid condition takes place.
Thus, to prevent this invalid condition, a clock circuit is introduced. The JK Flip Flop has four possible input combinations because of the addition of the clocked input. The four inputs are “logic 1”, ‘logic 0”. “No change’ and “Toggle”.
The circuit diagram of the JK Flip Flop is shown in the figure below:
The S and R inputs of the RS bistable have been replaced by the two inputs called the J and K input respectively.
Here J = S and K = R. The two-input AND gates of the RS flip-flop is replaced by the two 3 inputs NAND gates with the third input of each gate connected to the outputs at Q and Ǭ. This cross-coupling of the RS Flip-Flop is used to produce toggle action. As the two inputs are interlocked.
If the circuit is in the “SET” condition, the J input is inhibited by the status 0 of Q through the lower NAND gate. Similarly, the input K is inhibited by 0 status of Q through the upper NAND gate in the “RESET” condition. Slot 3d training games.
When both J and K are at logic “1”, the JK Flip Flop toggle.
The Truth Table of the JK Flip Flop is shown below.JKQǬDescriptionSame as for the RS Latch0000Memory No Change00010110Reset Q >> 001011001Set Q >> 11010Toggle1101Toggle1110Sr Latch Notes Template
JK Flip Flop is similar to RS flip flop with the feedback which enables only one of its input terminals. It eliminates the invalid condition which arises in the RS flip flop and put the input terminal either to set or reset condition one at a time.
When both the J and K inputs are at logic “1” at the same time and the clock input is pulsed HIGH, the circuit toggle from its SET state to a RESET or visa versa. Kvip latrine. When both the terminals are HIGH the JK flip-flop acts as a T type toggle flip-flop.
JK flip-flop has a drawback of timing problem known as “RACE”. The condition of RACE arises if the output Q changes its state before the timing pulse of the clock input has time to go in OFF state.
The timing pulse period (T) should be kept as short as possible to avoid the problem of timing.
This condition is not possible always thus a much-improved flip-flop named Master Salve JK Flip Flop was developed. This eliminates all the timing problems by using two RS flip-flop connected in series. One is for the “MASTER “ circuit, which triggers on the leading edge of the clock pulse. The other is called the “SLAVE” circuit, which triggers when the clock pulse is at the falling edge.Sr Latch ExampleRelated terms:
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Flip Flops-
*Sr Latch Notes Definition
*Sr Latch Notes Template
*Sr Latch Example
Before you go through this article, make sure that you have gone through the previous article on Flip Flops.
We have discussed-
*A Flip Flop is a memory element that is capable of storing one bit of information.
*It is also called as Bistable Multivibrator since it has two stable states either 0 or 1.
Whenever the clock signal is LOW, the inputs S and R are never going to affect the output. The clock has to be high for the inputs to get active. Thus, SR flip-flop is a controlled Bi-stable latch where the clock signal is the control signal. Again, this gets divided into positive edge triggered SR flip flop and negative edge triggered SR flip-flop. Thus, the output has two stable states based on the inputs which have been discussed below. #077 NOR Gate SR Latch. Set-Reset latch implemented with NOR gates. This circuit is another implementation of a Set-Reset flip-flop, this time using NOR gates. Sometimes this is referred to as a “NOR Latch”. A 74LS02 is used to provide the two NOR gates required. See the LEAP#061 SRLatch circuit for an implementation using BJTs. Lecture #11: Latches, Flops, and Metastability Paul Hartke Phartke@stanford.edu Stanford EE121 February 14, 2002 Administrivia. Make sure to fill out TA evaluations!!! – Incentive: 5 Point bonus on Lab 6. Lab 6 is only worth 60 – Everything is anonymous. Lab 6 Prelab is due Midnight on Thursday. Note that the internal latch inputs will both go from 1 to 0 if the S and R inputs are both 1 when the clock goes low. Hence we must never have S and R at 1 when the clock is 1. We make the following rules for changing inputs. ZDon’t change the inputs while the clock is asserted.
There are following 4 basic types of flip flops-
*SR Flip Flop
*JK Flip Flop
*D Flip Flop
*T Flip Flop
In this article, we will discuss about SR Flip Flop.SR Flip Flop-
*SR flip flop is the simplest type of flip flops.
*It stands for Set Reset flip flop.
*It is a clocked flip flop.Construction of SR Flip Flop-
There are following two methods for constructing a SR flip flop-
*By using NOR latch
*By using NAND latch1. Construction of SR Flip Flop By Using NOR Latch-
This method of constructing SR Flip Flop uses-
*NOR latch
*Two AND gatesLogic Circuit-
The logic circuit for SR Flip Flop constructed using NOR latch is as shown below-2. Construction of SR Flip Flop By Using NAND Latch-
This method of constructing SR Flip Flop uses-
*NAND latch
*Two NAND gatesLogic Circuit-
The logic circuit for SR Flip Flop constructed using NAND latch is as shown below-Logic Symbol-
The logic symbol for SR Flip Flop is as shown below-Truth Table-
Q casino and hotel california casino. The truth table for SR Flip Flop is as shown below-INPUTSOUTPUTSSRQn
(Present State)Qn+1
(Next State)000000110100011010011011110Indeterminate111IndeterminateTruth Table
The above truth table may be reduced as-INPUTSOUTPUTSREMARKSSRQn
(Present State)Qn+1
(Next State)States and Conditions00XQnHold State condition S = R = 001X0Reset state condition S = 0 , R = 110X1Set state condition S = 1 , R = 011XIndeterminateIndeterminate state condition S = R = 1Truth TableCharacteristic Equation-
Draw a k map using the above truth table-
From here-
Qn+1 = ( SR + SR’ ) ( Qn + Q’n ) + Qn ( S’R’ + SR’ )Qn+1 = S + QnR’Excitation Table-
The excitation table of any flip flop is drawn using its truth table.
What is excitation table?
For a given combination of present state Qn and next state Qn+1, excitation table tell the inputs required.QnQn+1SR000X0110100111X0Excitation Table
To gain better understanding about SR Flip Flop,
Next Article-JK Flip Flop
Get more notes and other study material of Digital Design.
Watch video lectures by visiting our YouTube channel LearnVidFun.SR Flip Flop | Diagram | Truth Table | Excitation TableDescriptionSr Latch Notes DefinitionSR flip flop is the simplest type of flip flops. SR Flip Flop Construction, Logic Circuit Diagram, Logic Symbol, Truth Table, Characteristic Equation & Excitation Table are discussed.AuthorGate VidyalayPublisher Logo
The JK Flip Flop is the most widely used flip flop. It is considered to be a universal flip-flop circuit. The sequential operation of the JK Flip Flop is the same as for the RS flip-flop with the same SET and RESET input.
The difference is that the JK Flip Flop does not the invalid input states of the RS Latch (when S and R are both 1). The JK Flip Flop name has been kept on the inventor name of the circuit known as Jack Kilby.
The basic symbol of the JK Flip Flop is shown below:
The basic NAND gate RS flip-flop suffers from two main problems.
*Firstly, the condition when S = 0 and R = 0 should be avoided.
*Secondly, if the state of S or R changes its state while the input which is enabled is high, the correct latching action does not occur.
Thus to overcome these two problems of the RS Flip-Flop, the JK Flip Flop was designed.
The JK Flip Flop is basically a gated RS flip flop with the addition of the clock input circuitry. When both the inputs S and R are equal to logic “1”, the invalid condition takes place.
Thus, to prevent this invalid condition, a clock circuit is introduced. The JK Flip Flop has four possible input combinations because of the addition of the clocked input. The four inputs are “logic 1”, ‘logic 0”. “No change’ and “Toggle”.
The circuit diagram of the JK Flip Flop is shown in the figure below:
The S and R inputs of the RS bistable have been replaced by the two inputs called the J and K input respectively.
Here J = S and K = R. The two-input AND gates of the RS flip-flop is replaced by the two 3 inputs NAND gates with the third input of each gate connected to the outputs at Q and Ǭ. This cross-coupling of the RS Flip-Flop is used to produce toggle action. As the two inputs are interlocked.
If the circuit is in the “SET” condition, the J input is inhibited by the status 0 of Q through the lower NAND gate. Similarly, the input K is inhibited by 0 status of Q through the upper NAND gate in the “RESET” condition. Slot 3d training games.
When both J and K are at logic “1”, the JK Flip Flop toggle.
The Truth Table of the JK Flip Flop is shown below.JKQǬDescriptionSame as for the RS Latch0000Memory No Change00010110Reset Q >> 001011001Set Q >> 11010Toggle1101Toggle1110Sr Latch Notes Template
JK Flip Flop is similar to RS flip flop with the feedback which enables only one of its input terminals. It eliminates the invalid condition which arises in the RS flip flop and put the input terminal either to set or reset condition one at a time.
When both the J and K inputs are at logic “1” at the same time and the clock input is pulsed HIGH, the circuit toggle from its SET state to a RESET or visa versa. Kvip latrine. When both the terminals are HIGH the JK flip-flop acts as a T type toggle flip-flop.
JK flip-flop has a drawback of timing problem known as “RACE”. The condition of RACE arises if the output Q changes its state before the timing pulse of the clock input has time to go in OFF state.
The timing pulse period (T) should be kept as short as possible to avoid the problem of timing.
This condition is not possible always thus a much-improved flip-flop named Master Salve JK Flip Flop was developed. This eliminates all the timing problems by using two RS flip-flop connected in series. One is for the “MASTER “ circuit, which triggers on the leading edge of the clock pulse. The other is called the “SLAVE” circuit, which triggers when the clock pulse is at the falling edge.Sr Latch ExampleRelated terms:
Register here: http://gg.gg/wbarq
https://diarynote.indered.space
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