Loading DocumentPrepared by: Ibrahim Mohamed El-bastawisi
4-14. Assume that the 4-bit arithmetic circuit of Fig. 4-9 is enclosed in one IC package.
Show the connections among two such ICs to form an 8-bit arithmetic circuit.
4-15. Design an arithmetic circuit with one selection variable S and two n-bit data inputs A and B. The circuit generates the following four arithmetic operations in conjunction with the input carry Cin.
Draw the logic diagram for the first two stages.
S | Cin=0 | Cin=1 |
|---|---|---|
0 | A+B (Add) | A+1 (increment) |
1 | A-1 (decrement) | A+B'+1 (subtract) |
First two stages of the Arithmetic unit with 2 selection variables
S | Cin | Yi | |
|---|---|---|---|
0 | 0 | Bi | Cin∧Bi |
0 | 1 | 0 | |
1 | 0 | 1 | Cin∨(Cin∧Bi) |
1 | 1 | Bi |
First two stages of the Arithmetic unit with 1 selection variables
4-16. Derive a combinational circuit that selects and generates any of the 16 logic functions listed in Table 4-5.
S1 | S0 | Function |
|---|---|---|
0 | 0 | A∧B (AND) |
0 | 1 | A⊙B (XNOR) |
1 | 0 | A⋏ˉB (NAND) |
1 | 1 | A (NOT) |
Stage i of the Logic Unit