Arduino与Proteus仿真实例-74HC148优先编码器驱动仿真

74HC148优先编码器驱动仿真

74HC148先级编码器接受 8 个输入请求行 0-7 并输出 3 个行 A0-A2。优先编码确保仅对最高阶数据线进行编码。提供级联电路（启用输入 EI 和启用输出 EO）以允许八进制扩展，而无需外部电路。所有数据输入和输出均在低逻辑电平有效。所有输入均通过内部二极管钳位至 VCC 和接地而免受静电放电损坏。

在前面的实例中，对74HC148做了介绍，请参考：

8051单片机Proteus仿真与开发实例-74HC148优先编码器驱动仿真

1、仿真驱动电路原理图

2、仿真代码实现

int latchPin = 8; //Pin connected to ST\_CP of 74HC595
int clockPin = 6; //Pin connected to SH\_CP of 74HC595
int dataPin = 7; //Pin connected to DS of 74HC595
byte IA0 = 2;
byte IA1 = 3;
byte IA2 = 4;
byte IGS = 5;
byte dat1 = 0;
byte dat2 = 0;
byte dat3 = 0;
byte dat4 = 0;
byte dat;

void \_74hc595\_send\_data(byte dat){
  //ground latchPin and hold low for as long as you are transmitting
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, dat);   
  //return the latch pin high to signal chip that it 
  //no longer needs to listen for information
  digitalWrite(latchPin, HIGH);
}

void setup(){
  Serial.begin(9600);
  pinMode(IA0,INPUT);
  pinMode(IA1,INPUT);
  pinMode(IA2,INPUT);
  pinMode(IGS,INPUT);

  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
}

void loop(){
  dat1 = digitalRead(IA0);
  dat2 = digitalRead(IA1);
  dat3 = digitalRead(IA2);
  dat4 = digitalRead(IGS);
  Serial.print("dat1,dat2,dat3,dat4=");
  Serial.print(dat1);
  Serial.print(',');
  Serial.print(dat2);
  Serial.print(',');
  Serial.print(dat3);
  Serial.print(',');
  Serial.print(dat4);
  Serial.println();
  dat = (((dat3 << 3) | (dat2 << 2) | (dat1 << 1) | (dat4 << 0)) & 0x0F);
  Serial.print("dat=");
  Serial.println(dat);
  switch(dat){
    case 0b1110:
    Serial.println("0");
    \_74hc595\_send\_data(1 << 0);
    break;
    case 0b1100:
    Serial.println("1");
    \_74hc595\_send\_data(1 << 1);
    break;
    case 0b1010:
    Serial.println("2");
    \_74hc595\_send\_data(1 << 2);
    break;
    case 0b1000:
    Serial.println("3");
    \_74hc595\_send\_data(1 << 3);
    break;
    case 0b0110:
    Serial.println("4");
    \_74hc595\_send\_data(1 << 4);
    break;
    case 0b0100:
    Serial.println("5");
    \_74hc595\_send\_data(1 << 5);
    break;
    case 0b0010:
    Serial.println("6");
    \_74hc595\_send\_data(1 << 6);
    break;
    case 0b0000:
    Serial.println("7");
    \_74hc595\_send\_data(1 << 7);
    break;
    case 0b1111:
    Serial.println("none");
    \_74hc595\_send\_data(0);
    break;
  }
  delay(10);
}