实验要求

该项目主要实现一个深度为8、位宽为8bit的同步FIFO存储单元。模块功能应包括读控制、写控制、同时读写控制、FIFO满状态、FIFO空状态等逻辑部分。
该项目由一个功能模块和一个testbench组成。其中功能模块的端口信号如下表所示。


提示：
（1）设定一个写地址waddr[2:0]，每来一个写使能wr，则写地址加一；
（2）设定一个读地址raddr[2:0]，每来一个读使能rd，则读地址加一；
（3）若同时读写，则读写地址不变，只是将输入数据din直接赋值给dout;
（4）FIFO中数据的个数cout=waddr-raddr;
（5）状态指示：

• 当cout=8时，FIFO满（full=1）;
• 当cout=6时，FIFO快满了（almost_full=1）;
• 当cout=4时，FIFO半满（半空）（half=1）;
• 当cout=2时，FIFO快空了（almost_empty=1）;
• 当cout=0时，FIFO空（empty=1）;

sfifo

module sfifo(clk,rst_n,data_in,wr,rd,full,empty,data_out,sfifo_cnt,half,almost_empty,almost_full);input clk;input rst_n;input [7:0] data_in;input wr;input rd;output full;output empty;output almost_full;output almost_empty;output half;output [7:0] data_out;output [3:0] sfifo_cnt;wire clk;wire rst_n;wire [7:0] data_in;wire wr;wire rd;wire full;wire empty;wire almost_full;wire almost_empty;wire half;reg [7:0] data_out;reg [3:0] sfifo_cnt;`define DEL 1 // Clock-to-output delayreg [7:0] sfifo_ram[0:7];  // sfifo_ram initializedreg [2:0] rd_ptr;  // Read pointerreg [2:0] wr_ptr;  // Write pointer assign empty = ( sfifo_cnt == 0 ) ? 1 : 0;  //Empty signalassign full  = ( sfifo_cnt == 8 ) ? 1 : 0;  //Full signalassign almost_full  = ( sfifo_cnt == 6 ) ? 1 : 0; //Almost Full signalassign almost_empty  = ( sfifo_cnt == 2 ) ? 1 : 0;//Almost Empty signalassign half  = ( sfifo_cnt == 4 ) ? 1 : 0;//HALF signal// sfifo_cnt changed// 当读有效, cnt--// 当写有效, cnt++always @( posedge clk or negedge rst_n) beginif( ~rst_n ) beginsfifo_cnt <= #`DEL 4'h0;endelse if( rd && ~wr ) beginsfifo_cnt <= #`DEL sfifo_cnt - 1;endelse if( ~rd && wr ) beginsfifo_cnt <= #`DEL sfifo_cnt + 1;endelse begin sfifo_cnt <= sfifo_cnt;endend      always @( posedge clk or negedge rst_n) beginif( ~rst_n ) beginrd_ptr <= #`DEL 3'h0;endelse if( rd ) beginif( rd_ptr == 3'h7 ) beginrd_ptr <= #`DEL 3'h0;endelse beginrd_ptr <= #`DEL rd_ptr +1;endendelse beginrd_ptr <= rd_ptr;endend    always @( posedge clk or negedge rst_n) beginif( ~rst_n ) beginwr_ptr <= #`DEL 3'h0;endelse if( wr ) beginif( wr_ptr == 3'h7 ) beginwr_ptr <= #`DEL 3'h0;endelse beginwr_ptr <= #`DEL wr_ptr +1;endendelse beginwr_ptr <= wr_ptr;endend always @( posedge clk or negedge rst_n) beginif( ~rst_n ) begindata_out <= #`DEL 8'h0;endelse if( wr ) beginsfifo_ram[wr_ptr] <= #`DEL data_in;endelse if( rd ) begin data_out <= #`DEL sfifo_ram[rd_ptr];endend      endmodule   

sfifo_test

module sfifo_test();reg clk;reg rst_n;reg [7:0] data_in;reg wr;reg rd;wire full;wire empty;wire almost_full;wire almost_empty;wire half;wire [7:0] data_out;wire [3:0] sfifo_cnt;initial beginrst_n=1;clk=0;wr=0;rd=0;data_in=0;#1 rst_n=0;#5 rst_n=1;#3 wr=1;#5 rd=1;#5 rd=0;#5 wr=0;#5 wr=1;#10 rd=1;#10 rd=0;endalways begin#5 clk=~clk;endalways @(posedge clk or negedge rst_n) beginif (~rst_n) begindata_in<=0;wr<=0;rd<=0;endelse begindata_in<=$random;endendinitial begin$dumpfile ("F:/Robei/practice/prac_07_sfifo/sfifo_test.vcd");$dumpvars;#5000;$stop;end//---Module instantiation---sfifo sfifo1(.clk(clk),.rst_n(rst_n),.data_in(data_in),.wr(wr),.rd(rd),.full(full),.empty(empty),.almost_full(almost_full),.almost_empty(almost_empty),.half(half),.data_out(data_out),.sfifo_cnt(sfifo_cnt));endmodule    

实验结果

整体波形

读

写

同时读写