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// Blink an LED provided an input clock
/* module */
module top (hwclk, mosi, led1, led2, led3, led4, led5, led6, led7, led8, clkout , out);
/* I/O */
input hwclk;
input mosi;
output led1;
output led2;
output led3;
output led4;
output led5;
output led6;
output led7;
output led8;
output clkout;
output out;
wire clkout;
/* Counter register */
reg [31:0] counter = 32'b0;
reg [8:0] shiftreg = 9'b1;
/* LED drivers */
assign led1 = shiftreg[0];
assign led2 = shiftreg[1];
assign led3 = shiftreg[2];
assign led4 = shiftreg[3];
assign led5 = shiftreg[4];
assign led6 = shiftreg[5];
assign led7 = shiftreg[6];
assign led8 = shiftreg[7];
assign clkout = hwclk;
assign out = shiftreg[8];
/* always */
always @ (negedge hwclk)
begin
shiftreg = (shiftreg << 1) + mosi;
end
endmodule
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