Memory Elements
November 9, 1998

• So far we have considered combinatorial logic.
• That is circuits for which the output depends only on the inputs.
• In many instances it is desirable to have the next output depend on the current output.
• A simple example is a counter, where the next number to be output is determined by the current number stored.
• Circuits that remember their current output or state are often called sequential logic.
• Clearly, sequential logic requires the ability to store the current state.
• In other words, memory is required by sequential logic circuits.
• We will investigate basic circuits that have the ability to store bits of data.