74HC4067/74HCT4067類比多工器可以切換16個類比腳位,只要接到MCU的一個類比腳位,
MCU就可以靠一個類比腳位,切換讀取74HC4067/74HCT4067類比多工器上的16個類比腳位,
在74HC4067/74HCT4067類比多工器上,s1,s2,s3,s4控制Y0-Y15的類比輸入腳位切換到到Z,
而Z接到Mega25602的類比腳位(如A0),因此只要控制s1,s2,s3,s4,Mega2560的A0就可以切換地讀取16個類比訊號源,
本範例的接腳為:
s0 --> digital 6;
s1 --> digital 5;
s2 --> digital 3;
s3 --> digital 2;
E --> digital 4; (設成Low output)
Z --> A0
Vcc --> 5V
GND --> GND
本範例參考: http://bildr.org/2011/02/cd74hc4067-arduino/
Arduino code:
//Mux control pins
int s0 = 6;
int s1 = 5;
int s2 = 3;
int s3 = 2;
int E = 4;
//Mux in "SIG" pin
int SIG_pin = 0;
void setup()
{
pinMode(s0,OUTPUT);
pinMode(s1,OUTPUT);
pinMode(s2,OUTPUT);
pinMode(s3,OUTPUT);
pinMode(E,OUTPUT);
digitalWrite(s0,LOW);
digitalWrite(s1,LOW);
digitalWrite(s2,LOW);
digitalWrite(s3,LOW);
digitalWrite(E,LOW);
Serial.begin(9600);
}
void loop()
{
//Loop through and read all 16 values
//Reports back Value at channel 6 is: 346
for(int i = 0; i < 16; i ++){
Serial.print("Value at channel ");
Serial.print(i);
Serial.print("is : ");
Serial.println(readMux(i));
delay(1000);
}
}
int readMux(int channel)
{
int controlPin[] = {s0, s1, s2, s3};
int muxChannel[16][4]={
{0,0,0,0}, //channel 0
{1,0,0,0}, //channel 1
{0,1,0,0}, //channel 2
{1,1,0,0}, //channel 3
{0,0,1,0}, //channel 4
{1,0,1,0}, //channel 5
{0,1,1,0}, //channel 6
{1,1,1,0}, //channel 7
{0,0,0,1}, //channel 8
{1,0,0,1}, //channel 9
{0,1,0,1}, //channel 10
{1,1,0,1}, //channel 11
{0,0,1,1}, //channel 12
{1,0,1,1}, //channel 13
{0,1,1,1}, //channel 14
{1,1,1,1} //channel 15
};
//loop through the 4 sig
for(int i = 0; i < 4; i ++){
digitalWrite(controlPin[i], muxChannel[channel][i]);
}
//read the value at the SIG pin
int val = analogRead(SIG_pin);
//return the value
return val;
}
接線圖 (有點混亂)
Serial Monitor: