题解 | #同步FIFO#常规计数器实现

`timescale 1ns/1ns

/**********************************RAM************************************/
module dual_port_RAM #(parameter DEPTH = 16,
					   parameter WIDTH = 8)(
	 input wclk
	,input wenc
	,input [$clog2(DEPTH)-1:0] waddr  
	,input [WIDTH-1:0] wdata      	
	,input rclk
	,input renc
	,input [$clog2(DEPTH)-1:0] raddr  
	,output reg [WIDTH-1:0] rdata 		
);

reg [WIDTH-1:0] RAM_MEM [0:DEPTH-1];

always @(posedge wclk) begin
	if(wenc)
		RAM_MEM[waddr] <= wdata;
end 

always @(posedge rclk) begin
	if(renc)
		rdata <= RAM_MEM[raddr];
end 

endmodule  

/**********************************SFIFO************************************/
module sfifo#(
	parameter	WIDTH = 8,
	parameter 	DEPTH = 16
)(
	input 					clk		, 
	input 					rst_n	,
	input 					winc	,
	input 			 		rinc	,
	input 		[WIDTH-1:0]	wdata	,

	output reg				wfull	,
	output reg				rempty	,
	output wire [WIDTH-1:0]	rdata
);

reg [$clog2(DEPTH)-1:0] w_addr,r_addr;

always@(posedge clk or negedge rst_n)begin
	if(~rst_n)begin
		w_addr <= 'b0;
	end
	else if(winc && ~wfull)begin
		w_addr <= w_addr + 1'b1;
	end
end

always@(posedge clk or negedge rst_n)begin
	if(~rst_n)begin
		r_addr <= 'b0;
	end
	else if(rinc && ~rempty)begin
		r_addr <= r_addr + 1'b1;
	end
end

reg [$clog2(DEPTH):0] cnt;
always@(posedge clk or negedge rst_n)begin
	if(~rst_n)begin
		cnt <= 'b0;
	end
	else if(winc && ~wfull)begin
		cnt <= cnt + 1'b1;
	end
	if(~rst_n)begin
		cnt <= 'b0;
	end
	else if(rinc && ~rempty)begin
		cnt <= cnt - 1'b1;
	end
end

always@(posedge clk or negedge rst_n)begin
	if(~rst_n)begin
		wfull <= 1'b0;
	end
	else if(cnt == DEPTH)begin
		wfull <= 1'b1;
	end
	else begin
		wfull <= 1'b0;
	end
	if(~rst_n)begin
		rempty <= 1'b0;
	end
	else if(cnt == 'b0)begin
		rempty <= 1'b1;
	end
	else begin
		rempty <= 1'b0;
	end
end

dual_port_RAM 
#(	
	.DEPTH(DEPTH),
	.WIDTH(WIDTH)
)
dual_port_RAM_u0
(
 	.wclk(clk),
	.wenc(winc&&~wfull),
	.waddr(w_addr),
	.wdata(wdata),      	
	.rclk(clk),
	.renc(rinc&&~rempty),
	.raddr(r_addr),
	.rdata(rdata) 	
);







    
endmodule