The JK flip-flop is the most widely used of all the flip-flops and can be
viewed as a universal flip-flop, since it can be configured to behave as an SR
flip-flop, a D flip-flop, or a T flip-flop. It is basically a gated SR flip-flop without
the illegal output states when J and K are equal or logic ‘1’.
The J-input is driven by the even LUT output (LUT0), and the K-input is driven by the odd LUT output (LUT1).
Figure 1. JK Flip-Flop
| R | J | K | OUT |
|---|---|---|---|
| 1 | X | X | Clear |
| 0 | 0 | 0 | Hold state (no change) |
| 0 | 0 | 1 | Clear |
| 0 | 1 | 0 | Set |
| 0 | 1 | 1 | Toggle |