2. November 2010
// Example to hook up a 74AC138 Decoder
// by defining the state of three outputs
// one can switch off 1 out of 8 outputs of the Decoder
// in this example NO Port manuipulation was used
// for the ease of understanding...
// constants -----------------------------
#define DATA1 8
#define DATA2 9
#define DATA3 10
// the setup -----------------------------
void setup() {
//define pins 8,9,10 as outputs
pinMode(DATA1, OUTPUT);
pinMode(DATA2, OUTPUT);
pinMode(DATA3, OUTPUT);
}
// the loop -----------------------------
void loop() {
for (byte x = 0; x<=8; x++){
// function see below
setPins(x);
delay(80);
}
}
// function definition --------------------
// the bits of the variable "number" are
// sent out to the decoder
void setPins(int number){
boolean d1 = bitRead(number, 0);
boolean d2 = bitRead(number, 1);
boolean d3 = bitRead(number, 2);
digitalWrite(DATA1, d1);
digitalWrite(DATA2, d2);
digitalWrite(DATA3, d3);
}
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