Digital Circuit Fundamentals 1 Unit 5 – 4-BIT Adder
Exercise 2 – Binary Addition and Carry
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to use input C0 of your adder. You will
verify your results by relating circuit waveforms to output binary sum values.
DISCUSSION
- A carry of 1 is activated when the C0 input, to the adder, is pulled to VCC. C0 pulled high
adds 1 to the data being summed. C0 pulled to VSS (common or 0V) has no effect on the data
being summed. - An oscilloscope can scan the output waveforms of the adder.
- The overflow output (C4) is active during the complete count 16 interval. This interval
equals the time during which the adder output is greater than 15: (C4)0000.