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input clk;
input [0:3] key;
output play, recrd, erase, save, address;
reg [0:3] next_state;
reg [0:3] current_state;
reg play, recrd, erase, save, address;
always @(posedge clk)
current_state = next_state;
always @(key or current_state)
begin
play = 1’b0;
recrd = 1’b0;
erase = 1’b0;
save = 1’b0;
address = 1’b0;
case (current_state)
main_st : begin
if (key == one)
next_state = review_st;
else if (key == two)
next_state = send_st;
else
next_state = main_st;
end
review_st:begin
if (key == one)
next_state = repeat_st;
else if (key == two)
next_state = save_st;
else if (key == three)
next_state = erase_st;
else if (key == pound)
next_state = main_st;
else
next_state = review_st;
end
repeat_st: begin
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SystemC 2.0 User’s Guide