ECE 09241 Lecture Notes - Clock Signal, Flight Attendant, Microsecond

• School: Rowan University
• Department: Electrical and Computer Engineering
• Course: ECE 09241

Document Summary

Intro to digital systems course notes: lecture 4. A sequential circuit"s output is dependent on the present and the past sequence of input values, which necessarily means the circuit stores at least one bit. In contrast, a combinational circuit"s output is dependent only on the present combination of input values. The simplest circuit for storing a bit is called a latch. An sr latch stores one bit, with an input s to set the latch to 1, an input r to reset the latch to 0, and with the stored bit appearing on output q. S and s are for "set", and r and r for "reset". Below is a circuit for an sr latch. Reminder: nor outputs 0 if any input is 1. Sr = 11 is problematic s = 1 and r = 1 causes a problem. The 1"s cause the nor gates to output 0"s. When s and r return to 0"s, then both gates output 1"s.