关于modelsim仿真出现NO DATA的问题，如何解决？ - 51Testing软件测试论坛

`timescale 1 ns / 1 ps
////////////////////////////////////////////////////////////////////////////////////
// Company: SMG
// Engineer: John Liu
//
// Create Date: 21:02:51 07/05/2022
// Design Name:
// Module Name: ADC0809
// Project Name: ADC0809
// Target Devices: EP3C25E144CBN & ADC0809
// Tool versions: 13.0
// Description: Interface Control for ADC0809
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
////////////////////////////////////////////////////////////////////////////////////
module ADC0809(
//input
input clk,
input rst_n,
input [2:0] add_in, //外部控制的通道选择信号
input [7:0] data_fromAD,
input EOC,
//output
output [2:0] add_out, //FPGA给ADC0809的通道选择信号
output [7:0] show_out, //传给上位机进行显示
output reg ALE, //d地址锁存允许信号
output reg START,
output reg OE, //输出允许信号
output reg clk_adc //ADC芯片的输入时钟
);
//参数
//状态机的8个状态常量
parameter IDLE1 = 3'b000,
ALE2 = 3'b001,
START_P3 = 3'b010,
START_N4 = 3'b011,
CHECK_EOC_P5 = 3'b100,
CHECK_EOC_N6 = 3'b101,
OE7 = 3'b110,
SEND_DATA8 = 3'd111;
parameter NUM = 50;
//定义中间变量
//reg [2:0] p_state ;
//reg [2:0] n_state ;
reg [2:0] state;
//reg ALE ;
//reg OE ;
//reg START;
reg [7:0] data_temp;
reg [7:0] count ; //分频器
//reg clk_adc; //adc时钟500kHZ
//时钟分频50MHz，20ns一个周期，现在要500KHz///////////////////////////////////
always@ (posedge clk or negedge rst_n) begin
if(!rst_n) begin
//p_state <= st0;
count <= 8'b0;
clk_adc <= 1'b0;
end
else if ((count==NUM-1)&& ( clk == 1'b1 )) begin
count <= 8'b0;
clk_adc <= ~clk_adc;
end
else
count = count +1'b1;
end
//三位地址信号传递//////////////////////////////////////////////////////////////
assign add_out = add_in;
//状态机////////////////////////////////////////////////////////////////////////
always@ (posedge clk_adc or negedge rst_n) begin
if(!rst_n) begin
state <= IDLE1; //进入初始状态
ALE <= 1'b0; //输出给ADC的地址锁存允许信号初始化一下
START <= 1'b0; //输出给ADC的转化启动信号初始化一下
OE <= 1'b0; //输出给ADC的数据输出允许信号初始化一下
data_temp <= 8'd0;
end
else begin
case(state)
IDLE1: begin //1
ALE <= 1'b0;
START <= 1'b0;
OE <= 1'b0;
state <= ALE2;
end
ALE2: begin //2
ALE <= 1'b1;
START <= 1'b0;
OE <= 1'b0;
state <= START_P3;
end
START_P3: begin //3
ALE <= 1'b0;
START <= 1'b1;
OE <= 1'b0;
state <= START_N4;
end
START_N4: begin //4
ALE <= 1'b0;
START <= 1'b0;
OE <= 1'b0;
state <= CHECK_EOC_P5;
end
CHECK_EOC_P5: begin //5
if(EOC == 1'b1)
state = CHECK_EOC_P5;
else
state = CHECK_EOC_N6; //检测到了低电平，说明开始转换
end
CHECK_EOC_N6: begin //6
if(EOC == 1'b0)
state <= CHECK_EOC_N6;//等待转换的结束
else
state <= OE7;
end
OE7: begin //7
OE <= 1'b1;
state <= SEND_DATA8;
end
SEND_DATA8: begin //8
data_temp <= data_fromAD;
state <= IDLE1;
end
default: begin
ALE <= 1'b0;
START <= 1'b0;
OE <= 1'b0;
state <= IDLE1;
end
endcase
end
end
//assign add_out = 3'b000;//选通IN0
assign show_out = data_temp;
endmodule

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`timescale 1 ns/ 1 ps
module ADC0809_vlg_tst();
// constants
// general purpose registers
reg eachvec;
// test vector input registers
reg EOC;
reg [2:0] add_in;
reg clk;
reg [7:0] data_fromAD;
reg rst_n;
// wires
wire ALE;
wire OE;
wire START;
wire [2:0] add_out;
wire clk_adc;
wire [7:0] show_out;
parameter T = 20; //时钟周期为20ns
// assign statements (if any)
ADC0809 i1 (
// port map - connection between master ports and signals/registers
.ALE(ALE),
.EOC(EOC),
.OE(OE),
.START(START),
.add_in(add_in),
.add_out(add_out),
.clk(clk),
.clk_adc(clk_adc),
.data_fromAD(data_fromAD),
.rst_n(rst_n),
.show_out(show_out)
);
initial
begin
// code that executes only once
// insert code here --> begin
clk = 0;
rst_n <= 0;
#(T+1)
rst_n <=1;
data_fromAD <= 8'h0; //暂且模拟输入初始化
EOC = 1'b1; //转换结束状态初始化
end
always #(T/2) clk = ~clk;
always add_in = 3'b010;
always @(negedge START) begin
#3000 //t_EOC
EOC <= 1'b0;
data_fromAD <= data_fromAD + 1'b1; //
#99000 //t_C
EOC <= 1'b1;
end
endmodule

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