(Solved): Digital logic question   The diagrams on the first page:   Problem 2. Subtraction w ...

Digital logic question

 

The diagrams on the first page:

 

Problem 2. Subtraction with Two's Complement Question 2 in the lab requires the construction of a 2-bit adder/subtractor using the 4-bit chip. To perform addition, compute input A+ input B as normal. To perform subtraction, Input A will remain the same, but Input B will need to be converted to its 2's Compliment. To compute \( A-B \), the formula is \( A+B ' 1 \), where \( B^{\prime} \) means inverting each bit of input B. Let \( \mathrm{C}_{i n} \) be the toggle between doing add and subtract, i.e. when \( \mathrm{Cin}_{10}=0 \), the circuit performs addifion, and when \( \mathrm{C}_{\mathrm{m}}=1 \), the circuit performs subtraction. If \( C_{i n}=0 \), then the circuit performs \( A+B+C=A+B+0 \) If \( C_{i n}=1 \), then the circuit performs \( A+B^{\prime}+C_{i n}=A+B^{\prime}+1 \) The remaining problem is inverting bits of \( \mathrm{B} \) when \( \mathrm{C}_{\mathrm{i}}=1 \) Solve this problem and you will have a 2-bit adderlsubtractor. For this question, do the following: 2.1 Explain how you manipulate the bits of \( B \) to do both add and subtract 2.2 Draw the logic diagram (not cirenif ellagram) of the 4bit adder/subtractor. For the Full Adder, use the logic symbol in the first page. Problem 3 1-Digit BCD Full Adder Leam about Binary Coded Decimal. Check the logic behind a 1-digit BCD full adder. Come up with a truth table and logic diagram for the BCD full adder. (Note: You have to implement the same question in the lab). Fig. 1. Logic Symbol for a 4-bit Full Adder Fig 2.IC 74LS283 Pinout with matching logic labels