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# JKFLIPFLOP

JK flip-flop

### Block Screenshot

### Contents

### Palette

### Description

The JK flip flop is the most versatile of the basic flip-flops. It has two inputs traditionally labeled
**J** (Set) and **K** (Reset).

When the inputs

**J**and**K**are different, the output**Q**takes the value of**J**at the next falling edge.When the inputs

**J**and**K**are both low, no change occurs in the output state.When the inputs are both high the output

**Q**will toggle from one state to other. It can perform the functions of the set/reset (SR) flip-flop and has the advantage that there are no ambiguous states.

The **!Q** output is the logical negation of **Q**

It can also act as a T flip-flop to accomplish toggling action if **J**
and **K** are tied together. This toggle application finds extensive use
in binary counters.

The user can set the initial output state with **Initial Value**
parameter.

The truth table of this block is:

Hold | ||||

Reset | ||||

Set | ||||

Toggle |

where * Q* is the previous state of

_{n-1}

*.*

`Q`_{n}

### Data types

The block supports the following types :

Inputs:

**J**: scalar. Scilab's int8 data type only.**clk**: scalar. Scilab's real double.**K**: scalar. Scilab's int8 data type only.

A positive input is considered as logical 1, a negative or a null input as logical 0.

Outputs: scalar. Scilab's int8 data type.

### Dialog box

**Initial Value**Initial state of the

**Q**output.Properties : Type 'vec' of size 1.

### Default properties

**always active:**no**direct-feedthrough:**yes**zero-crossing:**no**mode:**no**regular inputs:****- port 1 : size [1,1] / type 5****- port 2 : size [1,1] / type 1****- port 3 : size [1,1] / type 5****regular outputs:****- port 1 : size [1,1] / type 5****- port 2 : size [1,1] / type 5****number/sizes of activation inputs:**0**number/sizes of activation outputs:**0**continuous-time state:**no**discrete-time state:**no**object discrete-time state:**no**name of computational function:***csuper*

### Example

The following example builds a 3 bits asynchronous counter with JK flipflops wired as T flipflops. You can show on the
right the timing diagram of the * Q*
to

_{0}

*outputs of counter. Open this example in Xcos*

`Q`_{2}

### Interfacing function

### See also

- DLATCH — D latch flip-flop
- DFLIPFLOP — D flip-flop
- SRFLIPFLOP — SR flip-flop

### Authors

**Fady NASSIF** - INRIA

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