YILDIRIM BEYAZIT UNIVERSITY ECE 205 – DIGITAL DESIGN LABORATORY MANUAL – 5 – Arithmetic Operations in Digital Circuits Objectives:
Implementions of Full Adder and Full Subtractor circuits with necessary integrated circuits (IC)
Designing 2 bit calculator operating addition and subtraction
Equipment:
Breadboard, various IC gates, LEDs and wires
Laboratory Exercise: 1) Full Adder & Full Subtractor
Check Point 1! Show Truth Tables each of your circuit. Check Point 2! Show Logic Diagrams each of your circuits. Check Point 3! Show Wiring Diagrams including the package identifiers and pin numbers. Check Point 4! Implement your designs on breadboard making connections properly. Check Point 5! Connect LEDs to outputs(such as sum&carry) with different colours in order to verify their Truth Tables.
2) 2-bit Calculator
At this part, you are expected to construct a calculator that operates addition or subtraction of 2bit numbers represented as X and Y
Least Significant Bits (LSB) and Most Significant Bits (MSB) of binary numbers are evaluated seperately. For 2-bit calculator, firstly, build addition circuit that has been planned on first breadboard. After that, build another circuit that is expected to complete subtraction task of our calculator to second breadboard. **Do not forget connecting the inputs for X 1, X0, Y1 and Y0 together. Each of the inputs should have only one cable for simplicity. Check Point 6! Implement your designs on breadboard making connections properly. Check Point 7! Connect LEDs to outputs to verify the calculating operation.
If the circuit is not working properly: Work backwards. First check the gate which produces the output (use a long wire connected to a logic indicator). If you discover that some of its inputs are incorrect; then check the gates which produce these incorrect inputs, and so on.
Appendix: Pinouts for 74XX Series ICs present in Laboratory * Note That Pin14 is Vcc and Pin7 is Ground for all IC’s