-
-/*
- Shift Register Example
- Turning on the outputs of a 74HC595 using an array
-
- Hardware:
- * 74HC595 shift register
- * LEDs attached to each of the outputs of the shift register
-
- */
-//Pin connected to ST_CP of 74HC595
-int latchPin = 8;
-//Pin connected to SH_CP of 74HC595
-int clockPin = 12;
-////Pin connected to DS of 74HC595
-int dataPin = 11;
-
-//holders for infromation you're going to pass to shifting function
-byte data;
-byte dataArray[10];
-
-void setup() {
- //set pins to output because they are addressed in the main loop
- pinMode(latchPin, OUTPUT);
- Serial.begin(9600);
-
- //Arduino doesn't seem to have a way to write binary straight into the code
- //so these values are in HEX. Decimal would have been fine, too.
- dataArray[0] = 0xFF; //11111111
- dataArray[1] = 0xFE; //11111110
- dataArray[2] = 0xFC; //11111100
- dataArray[3] = 0xF8; //11111000
- dataArray[4] = 0xF0; //11110000
- dataArray[5] = 0xE0; //11100000
- dataArray[6] = 0xC0; //11000000
- dataArray[7] = 0x80; //10000000
- dataArray[8] = 0x00; //00000000
- dataArray[9] = 0x38; //11100000
-
- //function that blinks all the LEDs
- //gets passed the number of blinks and the pause time
- blinkAll_2Bytes(2,500);
-}
-
-void loop() {
-
- for (int j = 0; j < 10; j++) {
- //load the light sequence you want from array
- data = dataArray[j];
- //ground latchPin and hold low for as long as you are transmitting
- digitalWrite(latchPin, 0);
- //move 'em out
- shiftOut(dataPin, clockPin, data);
- //return the latch pin high to signal chip that it
- //no longer needs to listen for information
- digitalWrite(latchPin, 1);
- delay(300);
- }
-}
-
-
-
-// the heart of the program
-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<<i) ) {
- pinState= 1;
- }
- else {
- pinState= 0;
- }
-
- //Sets the pin to HIGH or LOW depending on pinState
- digitalWrite(myDataPin, pinState);
- //register shifts bits on upstroke of clock pin
- digitalWrite(myClockPin, 1);
- //zero the data pin after shift to prevent bleed through
- digitalWrite(myDataPin, 0);
- }
-
- //stop shifting
- digitalWrite(myClockPin, 0);
-}
-
-
-//blinks the whole register based on the number of times you want to
-//blink "n" and the pause between them "d"
-//starts with a moment of darkness to make sure the first blink
-//has its full visual effect.
-void blinkAll_2Bytes(int n, int d) {
- digitalWrite(latchPin, 0);
- shiftOut(dataPin, clockPin, 0);
- shiftOut(dataPin, clockPin, 0);
- digitalWrite(latchPin, 1);
- delay(200);
- for (int x = 0; x < n; x++) {
- digitalWrite(latchPin, 0);
- shiftOut(dataPin, clockPin, 255);
- shiftOut(dataPin, clockPin, 255);
- digitalWrite(latchPin, 1);
- delay(d);
- digitalWrite(latchPin, 0);
- shiftOut(dataPin, clockPin, 0);
- shiftOut(dataPin, clockPin, 0);
- digitalWrite(latchPin, 1);
- delay(d);
- }
-}
-
-
-