Warp-SE/cpld/CNT.v

module CNT(
	/* FSB clock and AS detection */
	input FCLK, input CACT,
	/* Refresh request */
	output RefReq, output RefUrgent, input RefAck,
	/* Timeout signals */
	output reg TimeoutA, output reg TimeoutB);
	
	/* Refresh counter */
	reg [7:0] RefCnt = 0;
	reg RefDone = 0;
	assign RefReq = ~RefDone;
	assign RefUrgent = RefCnt[7] && RefCnt[6] && RefCnt[5] && ~RefDone;
	always @(posedge FCLK) begin
		RefCnt <= RefCnt+1;
		if (RefCnt==0) RefDone <= 0;
		else if (RefAck) RefDone <= 1;
	end

	/* Timeout signals */
	reg TimeoutBPre;
	always @(posedge FCLK) begin
		if (~CACT) begin
			TimeoutA <= 0;
			TimeoutBPre <= 0;
			TimeoutB <= 0;
		end else begin
			if (RefCnt[6:0]==0) TimeoutA <= 1;
			if (RefCnt==0) TimeoutBPre <= 1;
			if (RefCnt==0 && TimeoutBPre) TimeoutB <= 1;
		end
	end

endmodule