Basics

Registers / Counters

Registers

A shift register is a group of flip flops set up in line so their inputs and outputs are connected together : the data is then shifted down the line when the circuit is activated.

Shift registers can have parallel and/or serial inputs and outputs.

The type used here has both serial and parallel input and serial and parallel output.

It is also bi-directional and allows to vary the direction of the shift register.

• 1D is the serial input for counting up (C1 →)
• 2D is the serial input for counting down (C2 ←)
• 3D are the parallel inputs for counting up or down. Data can be first stored with the Set input (C3).

Counters

Counters will count in binary when you provide a clock signal ("+" input for counting up, "-" input for counting down).

Ouput can be Preset (Data available on the D ports is stored whan a signal is applied on the "C" input), and Output can be reset with the "R" input".