// Copy Right(C) Makoto IKEDA, VDEC University of Tokyo 1998.
module	Counter(DIO,ck,Reset, PinCtr , CarryOut	);
	inout	[3:0]	DIO;
	input	ck, Reset, PinCtr;
	output	CarryOut;

	reg	CarryOut;
	reg	[3:0]	D;

	assign	DIO = (PinCtr == 0 ? (D):('bz));

	always @(posedge ck) begin
		if( Reset ) begin	CarryOut = 0;	D=0;	end
		else if( PinCtr ) begin	CarryOut = 0;	D = DIO;end
		else if( D == 15 ) begin CarryOut = 1;	D = 0;	end
		else begin D =  D + 1;	CarryOut = 0;	end
	end
endmodule