Description

1.[40 marks] Implement the finite state machine the next state function of which is shown in Table 1. The machine takes a two-bit input (Y[1:0]). The output function is not specified and can be ignored for this assignment. Suppose
Table 1. Next state function
Current state Input (Y[1:0]) Next state
S0 2’bxx S1
S1 2’bxx S2
S2 2’bxx S3
S3 2’b00 S4
S3 2’b01 S5
S3 2’b1x S6
S4 2’bxx S7
S5 2’bxx S7
S6 2’bxx S7
S7 2’bxx S8
S8 2’bxx S9
S9 2’bxx S10
S10 2’b00 S11
S10 2’b01,
2’b1x S12
S11 2’bxx S0
S12 2’bxx S0

a state incrementer can be used to compute the next state along with dispatch ROMs, a microcode ROM, and a state selection multiplexer. The microcode ROM takes only the current state as input to look up a row and outputs the branch control for computing the next state (note that Y cannot be used as an input to the microcode ROM).
The ROMs should be implemented as arrays and initialized within an initial block. The current state should be displayed on each rising clock edge in your top module. Two time units before each rising clock edge a new input is sent to the FSM (note that the input is two bits), but the state change occurs on rising edges only. Model a propagation delay of two time units in the state registers. The clock should have a cycle time of ten time units with 50% duty. Simulate for ten clock cycles.
2.[60 marks] Construct a module that takes as input four three-bit values treated as unsigned numbers and computes the index of the smallest value. For example, if the inputs are 110, 010, 001, and 111, the output is 2 indicating that the input at position two is the smallest (input index starts at zero on the left hand side and ends at three on the right hand side). Display the output index in your top module. Simulate for ten different input sets. Keep a delay of one time unit between two consecutive input sets.
Submission: Submit your verilog files named clearly. Prefix the file names for Q1 using A5Q1 and those for Q2 using A5Q2 . Email the files as attachment to cs220spring2021submit@gmail.com. The subject line of the email MUST be the following (replace N by your group number): Assignment#5 submission for Group#N
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