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// from usb_rx_phy
module usb_phy_test01(clk, rst, rx_en, fs_ce);
input clk, rst;
input rx_en;
output reg fs_ce;
reg [1:0] dpll_next_state;
reg [1:0] dpll_state;
always @(posedge clk)
dpll_state <= rst ? 0 : dpll_next_state;
always @*
begin
fs_ce = 1'b0;
case(dpll_state)
2'h0:
if(rx_en) dpll_next_state = 2'h0;
else dpll_next_state = 2'h1;
2'h1:begin
fs_ce = 1'b1;
if(rx_en) dpll_next_state = 2'h3;
else dpll_next_state = 2'h2;
end
2'h2:
if(rx_en) dpll_next_state = 2'h0;
else dpll_next_state = 2'h3;
2'h3:
if(rx_en) dpll_next_state = 2'h0;
else dpll_next_state = 2'h0;
endcase
end
endmodule
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