Question

Design (and then verify your design by simulating it) a two-bit counter that counts up or down. Use an enable input E to determine whether the counter is on or off: if E = 0 the counter is disabled and remains at its present count even if clock pulses are applied. If E = 1, the counter is enabled and a second input, x, determines the direction of the count: if x = 1 the circuit counts upward 00, 01, 10, 11, repeat; if x = 0 the circuit counts downward 11, 10, 01, 00, repeat. So, design the circuit with E and x as inputs. Test in verilog

This task has two parts: in section 2 you will design a binary counter circuit and simulate it to verify your design; then, in section 3, you'll practice those same design skills to implement and functionally identify) the circuit specified in a given state diagram and then simulate your design to verify it again. For your designs, use IC types 7476 and/or 7474, whose pins and functions shown in figures 1 and 2, and choose any type of gate that will minimize the total number of ICs used. (Refer to section 5.7 in the text.) 2 10 PR 15 9 4 43 PR 11 @ J 2 PR 5 12 PR 9 D D 1 6 > CK » СК Vcc=pin 5 GND = pin 13 3 11 VC - pin 14 GND = pin 7 16 14 12 10 РСК K K > CK Q CLR 6 8 Q CLR CLR CLR 8 13 Function table Function table Inputs Outputs Inputs Outputs Preset Clear Clock K e Preset Clear Clock D Q 0 0 1 0 0 1 1 0 0 X X X х X X X X X 0 1 0 0 1 1 0 0 Х Х х Х х Х 1 0 1 0 1 1 1 1 1 1 1 1 1 0 0 1 0 1 0 1 1 No change 0 1 1 0 Toggle + 1 0 0 0 1 1 1 0 X No change 1 1 1 1 Figure 1: IC 7476 pinout Figure 2: IC 7474 pinout 2 Up-Down Counter with Enable Design (and then verify your design by simulating it) a two-bit counter that counts up or down. Use an enable input E to determine whether the counter is on or off: if E = 0 the counter is disabled and remains at its present count even if clock pulses are applied. If E = 1, the counter is enabled and a second input, X, determines the direction of the count: if x = 1 the circuit counts upward 00, 01, 10, 11, repeat; if x = 0 the circuit counts downward 11, 10, 01, 00, repeat. So, design the circuit with E and x as inputs.

Answer 1

2-bit up-down Counter with Enable (E): Counter counts up words if => 00, 01, 10, 11,00, down wolds it 20 = 0 > 11, 10, oi, oo, 11... stalys on same state it E=0 No state change Truth Table with above Conditions Excitation Tables t E Qt lo DI Do D 0 o 0 o 0 0 0 0 o 0 0 0 D - o - - O - - - 0 0 - 0 0. - - O 0 O 0 - - O 0 0 - 0 0 0 0 - - - - o o 0 D for 0 Calculation 0 0 0 0 0 0 - - - 0 EX 00 10 oll? - Q ao 0 0 0 0 0 o 0 0 - 0 - 0 0 0 0) 0 0 0. T 0 - o 0 - 0 - o 1 10 0 LI - - - 1 ( 0 0 1 0 D, = Q, E t Q Ex + Q Ex D, = Q, Et E (@x +ē c) - 0 o 1 0 D, = Q E t E (@Or) 0 0 o 0 - Calculation for Do 00 ol 10 ce do 00 0 D Do = .00 % E tEą ao+Q, QE t Q Q a (Q E t do E) + a, (EtQE - ol Ilo 0 0 si D &, Q. © E) + Q, COE) 10 19 0 10 19 Q

fos D., D. So we Calculated Expressions Q, E tEQ,00) Do E circuit Diagram: 2 ס מכס, ( Q. Do Q 2 Counter E clk Sequential circuit