In VHDL, when we want to remember a value it must be stored in a VARIABLE.

More Questions from Counters

• The term synchronous, as applied to counter operations, means that the counter is clocked such that each flip-flop in the counter is triggered at the same time.
• A ripple counter is an asynchronous counter.
• Shift registers are used to store and transfer data.
• A J-K flip-flop excitation table lists the present state, the next state, and the J and K levels required to produce each transition.
• Counters are generally decoded in order to determine their count state.
• Phototransistors have varying resistance from collector to emitter, depending on how much light strikes them.
• An asynchronous counter differs from a synchronous counter in the method of clocking.
• When a J-K flip-flop is used in a circuit, we only have to consider the level at J and K at the active clock edge to know the states of the outputs.
• The MOD number of a Johnson counter will always be equal to one-half the number of flip-flops in the counter.
• In a synchronous counter, each state is clocked by the same pulse.

Discussion & Comments