Final answer:
If we want to write Verilog code for the given 1 flip-flop machine (M₂), we can use an always block to describe the behavior of the flip-flop based on the inputs X and Y.
Here's the Verilog code:
```verilog
module flip_flop_M2 (
input wire X,
input wire Y,
output reg Q
);
always (at)(X, Y)
begin
case({X, Y})
2'b00: Q <= 1'b0; // reset
2'b01: Q <= 1'b1; // set
2'b10: Q <= ~Q; // toggle
2'b11: Q <= Q; // no change
endcase
end
endmodule
```
Step-by-step explanation:
1. The `flip_flop_M2` module takes two input signals, X and Y, and has an output signal Q, which represents the state of the flip-flop.
2. The `always (at)(X, Y)` block ensures that the behavior of the flip-flop is sensitive to changes in the X and Y inputs.
3. Inside the `always` block, a `case` statement is used to define the behavior of the flip-flop based on the input values {X, Y}.
4. The cases 2'b00, 2'b01, 2'b10, and 2'b11 represent the four possible input combinations {X, Y} specified in the question.
5. For each case, the value of the output Q is assigned accordingly:
- - 2'b00 (X=0, Y=0): Q is set to 1'b0, indicating a reset.
- - 2'b01 (X=0, Y=1): Q is set to 1'b1, indicating a set.
- - 2'b10 (X=1, Y=0): Q is toggled by assigning it the complement (~) of its current value.
- - 2'b11 (X=1, Y=1): Q remains unchanged.
6. The `endcase` statement ends the case block, and the `end` statement closes the `always` block.
This Verilog code describes the behavior of the flip-flop machine M₂ based on the given truth table. Make sure to use this code if you are working on Stations 2, 4, 6, or 8.