//**************************************************************// // Name : shiftOutCode, Dual Binary Counters // // Author : Carlyn Maw, Tom Igoe // // Date : 25 Oct, 2006 // // Version : 1.0 // // Notes : Code for using a 74HC595 Shift Register // // : to count from 0 to 255 // //**************************************************************// //Pin connected to ST_CP of 74HC595 int latchPin = A1; //Pin connected to SH_CP of 74HC595 int clockPin = A0; ////Pin connected to DS of 74HC595 int dataPin = A2; void setup() { //Start Serial for debuging purposes Serial.begin(9600); //set pins to output because they are addressed in the main loop pinMode(latchPin, OUTPUT); } void loop() { //count up routine for (int j = 0; j < 256; j++) { //ground latchPin and hold low for as long as you are transmitting digitalWrite(latchPin, 0); //count up on GREEN LEDs shiftOut(dataPin, clockPin, j); //count down on RED LEDs shiftOut(dataPin, clockPin, 255-j); //return the latch pin high to signal chip that it //no longer needs to listen for information digitalWrite(latchPin, 1); delay(1000); } } void shiftOut(int myDataPin, int myClockPin, byte myDataOut) { // This shifts 8 bits out MSB first, //on the rising edge of the clock, //clock idles low //internal function setup int i=0; int pinState; pinMode(myClockPin, OUTPUT); pinMode(myDataPin, OUTPUT); //clear everything out just in case to //prepare shift register for bit shifting digitalWrite(myDataPin, 0); digitalWrite(myClockPin, 0); //for each bit in the byte myDataOut� //NOTICE THAT WE ARE COUNTING DOWN in our for loop //This means that %00000001 or "1" will go through such //that it will be pin Q0 that lights. for (i=7; i>=0; i--) { digitalWrite(myClockPin, 0); //if the value passed to myDataOut and a bitmask result // true then... so if we are at i=6 and our value is // %11010100 it would the code compares it to %01000000 // and proceeds to set pinState to 1. if ( myDataOut & (1<