Question

state machine is omployes to count coins at a toll booth. The machine has two inputs N and D. N I when a nickel is received and DI when a dime is received. In four states design a machine that will count to 20 cents, giving an output of "1" when receiving the correct amount of 20 cents. Omit al activity when N or D0. Also N I and D-1 will not occur simultaneously. dentify your states as: 00 initial state; O1 as counted $0.05 state; 11 as counted $0.10 state, 10 as counted $0.15. When in the 10 state, receiving a N-1 or D- l will return back to the initial state 00 with a"1" output. This means you can still get a "I"output if customer pays S0.25 a) Draw the state diagram showing the four states with the two inputs of D and b) Draw the state transition table with output. Include 4 states and the 2 inputs. c) Draw the circuit for just the output Z using NAND gates. 5 pts

Answer 1

NHD 00/0 104 osf 10/0 NDİZ oyo 0100o iol 10 0 o/o Jj 01/0 EALy FS

STATE	PRESENT STATE		INPUTs		NEXT STATE		OUTPUT
	Q1	Q0	N	D	Q1+	Q0+	Z
Initial	0	0	0	0	X	X	X
	0	0	0	1	1	1	0
	0	0	1	0	0	1	0
	0	0	1	1	X	X	X
$0.05	0	1	0	0	X	X	X
	0	1	0	1	1	0	0
	0	1	1	0	1	1	0
	0	1	1	1	X	X	X
$0.15	1	0	0	0	X	X	X
	1	0	0	1	0	0	1
	1	0	1	0	0	0	1
	1	0	1	1	X	X	X
$0.10	1	1	0	0	X	X	X
	1	1	0	1	0	0	1
	1	1	1	0	1	0	0
	1	1	1	1	X	X	X

ND 5C

Q1 X1 N x1