如何在缺少FPGA硬件的情况下学习数字电路

数字电路课程的学习早已经不可能忽视Verilog HDL的设计了，如果以后考研读通信、信号处理等方向的专业硕士（专硕）的话，就更是必备的技能。但是在手头暂时没有FPGA硬件的情况下，Verilog HDL不能落地，此时如何想办法弥补呢？单纯的Protesu仿真是不够的，因为Proteus库中缺少FPGA，只能退而求其次，Proteus中选择古老的MSI进行仿真，同时Diamond中进行Verilog设计，ModelSim中做功能仿真。下面以显示译码器为例，讲解学习过程。

1. Diamond编写Verilog code和testbench

module seg7 (bcd, leds);
    input [3:0] bcd;
    output reg [1:7] leds;
    always @(bcd)
        case (bcd) //abcdefg
            0: leds = 7'b1111110;
            1: leds = 7'b0110000;
            2: leds = 7'b1101101;
            3: leds = 7'b1111001;
            4: leds = 7'b0110011;
            5: leds = 7'b1011011;
            6: leds = 7'b1011111;
            7: leds = 7'b1110000;
            8: leds = 7'b1111111;
            9: leds = 7'b1111011;
            default: leds = 7'bx;
        endcase
endmodule

`timescale 1ns/100ps
module seg7_tb ();
    reg [3:0] bcd;
    wire [1:7] leds; //abcdefg
    initial begin
        bcd = 0;
        #20 bcd = 1;
        #20 bcd = 2;
        #20 bcd = 3;
        #20 bcd = 4;
        #20 bcd = 5;
        #20 bcd = 6;
        #20 bcd = 7;
        #20 bcd = 8;
        #20 bcd = 9;
        #40;
    end
    seg7 dut (
        .bcd(bcd),
        .leds(leds)
    );
endmodule

2. Modelsim中仿真，适合驱动共阴极数码管（正逻辑）

3. Arduino编写生成测试信号的程序，即依次产生0~9（8421BCD）

void setup() {

  pinMode(13, OUTPUT);　　//MSB
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(10, OUTPUT);　　//LSB
}

void loop() {
 
  digitalWrite(13, LOW);  
  digitalWrite(12, LOW); 
  digitalWrite(11, LOW);  
  digitalWrite(10, LOW);   
  delay(500);                     
  digitalWrite(13, LOW);  
  digitalWrite(12, LOW); 
  digitalWrite(11, LOW);  
  digitalWrite(10, HIGH);   
  delay(500);
  digitalWrite(13, LOW);  
  digitalWrite(12, LOW); 
  digitalWrite(11, HIGH);  
  digitalWrite(10, LOW);   
  delay(500);
  digitalWrite(13, LOW);  
  digitalWrite(12, LOW); 
  digitalWrite(11, HIGH);  
  digitalWrite(10, HIGH);   
  delay(500);
  digitalWrite(13, LOW);  
  digitalWrite(12, HIGH); 
  digitalWrite(11, LOW);  
  digitalWrite(10, LOW);   
  delay(500);  
  digitalWrite(13, LOW);  
  digitalWrite(12, HIGH); 
  digitalWrite(11, LOW);  
  digitalWrite(10, HIGH);   
  delay(500);  
  digitalWrite(13, LOW);  
  digitalWrite(12, HIGH); 
  digitalWrite(11, HIGH);  
  digitalWrite(10, LOW);   
  delay(500);  
  digitalWrite(13, LOW);  
  digitalWrite(12, HIGH); 
  digitalWrite(11, HIGH);  
  digitalWrite(10, HIGH);   
  delay(500);  
  digitalWrite(13, HIGH);  
  digitalWrite(12, LOW); 
  digitalWrite(11, LOW);  
  digitalWrite(10, LOW);   
  delay(500);  
  digitalWrite(13, HIGH);  
  digitalWrite(12, LOW); 
  digitalWrite(11, LOW);  
  digitalWrite(10, HIGH);   
  delay(500); 

}