SR Flip-flop

Purpose

Implement set-reset flip-flop

Library

Control / Logical

Description

../../_images/srflipflop.svg

The SR Flip-flop behaves like a pair of cross-coupled NOR logic gates. The output values correspond to the following truth table:

S

R

Q

/Q

0

0

No change

No change

0

1

0

1

1

0

1

0

1

1

Restricted (0)

Restricted (0)

The combination S = R = 1 is restricted because both outputs will be set to 0, violating the condition Q = not(/Q). If both inputs change from 1 to 0 in the same simulation step, Q will be set to 0 and /Q to 1.

Parameters

Initial state

The state of the flip-flop at simulation start.

Probe Signals

S

The input signal S.

R

The input signal R.

Q

The output signals Q.

/Q

The output signals /Q.