added 4K bram

openfpga_flow/openfpga_cell_library/verilog/dpram4k.v

@@ -0,0 +1,56 @@
+//-----------------------------------------------------
+// Design Name : dual_port_ram
+// File Name   : dpram.v
+// Function    : Dual port RAM 8x512 
+// Coder       : Xifan Tang
+//-----------------------------------------------------
+
+module dpram_512x8 (
+	input clk,
+	input wen,
+	input ren,
+	input[0:8] waddr,
+	input[0:8] raddr,
+	input[0:7] d_in,
+	output[0:7] d_out );
+
+		dual_port_sram memory_0 (
+			.wclk		(clk),
+			.wen		(wen),
+			.waddr		(waddr),
+			.data_in	(d_in),
+			.rclk		(clk),
+			.ren		(ren),
+			.raddr		(raddr),
+			.d_out		(d_out) );
+
+endmodule
+
+module dual_port_sram (
+	input wclk,
+	input wen,
+	input[0:8] waddr,
+	input[0:7] data_in,
+	input rclk,
+	input ren,
+	input[0:8] raddr,
+	output[0:7] d_out );
+
+	reg[0:7] ram[0:511];
+	reg[0:7] internal;
+
+	assign d_out = internal;
+
+	always @(posedge wclk) begin
+		if(wen) begin
+			ram[waddr] <= data_in;
+		end
+	end
+
+	always @(posedge rclk) begin
+		if(ren) begin
+			internal <= ram[raddr];
+		end
+	end
+
+endmodule