ShiftOut Tutorial. Maria Taylor

Transcription

1 ShiftOut Tutorial Maria Taylor The Shift register works from Left to Right. The side with the indent is Up indicating that the left pin is #1 and the right pin is #16. Step #1: Assess the board. Depict top from bottom, left from right and understand the order of the pins. Step two: o GND (Pin 8) to ground o Vcc (Pin 16) to 5v o OE (Pin 13) to Ground o MR (Pin 10 to 5v Step Three: o DS (Pin 14) to Arduino Pin 11

2 o SH_CP (Pin 11) to Arduino Pin 12 o ST_CP (Pin 12) to Arduino Pin 8 Step Four: o Add 8 Leds with 220 ohm resistors. Code 1: Checks Voltage //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; void setup() { //set pins to output so you can control the shift register pinmode(latchpin, OUTPUT);

3 pinmode(clockpin, OUTPUT); pinmode(datapin, OUTPUT); void loop() { // count from 0 to 255 and display the number // on the LEDs for (int numbertodisplay = 0; numbertodisplay < 256; numbertodisplay++) { // take the latchpin low so // the LEDs don't change while you're sending in bits: digitalwrite(latchpin, LOW); // shift out the bits: shiftout(datapin, clockpin, MSBFIRST, numbertodisplay); //take the latch pin high so the LEDs will light up: digitalwrite(latchpin, HIGH); // pause before next value: delay(500); Code Two: Makes Lights Blink 1 by 1 */ //Pin connected to latch pin (ST_CP) of 74HC595 const int latchpin = 8; //Pin connected to clock pin (SH_CP) of 74HC595 const int clockpin = 12; ////Pin connected to Data in (DS) of 74HC595 const int datapin = 11; void setup() { //set pins to output because they are addressed in the main loop

4 pinmode(latchpin, OUTPUT); pinmode(datapin, OUTPUT); pinmode(clockpin, OUTPUT); Serial.begin(9600); Serial.println("reset"); void loop() { if (Serial.available() > 0) { // ASCII '0' through '9' characters are // represented by the values 48 through 57. // so if the user types a number from 0 through 9 in ASCII, // you can subtract 48 to get the actual value: int bittoset = Serial.read() - 48; // write to the shift register with the correct bit set high: registerwrite(bittoset, HIGH); // This method sends bits to the shift register: void registerwrite(int whichpin, int whichstate) { // the bits you want to send byte bitstosend = 0; // turn off the output so the pins don't light up // while you're shifting bits: digitalwrite(latchpin, LOW); // turn on the next highest bit in bitstosend: bitwrite(bitstosend, whichpin, whichstate); // shift the bits out: shiftout(datapin, clockpin, MSBFIRST, bitstosend);

5 // turn on the output so the LEDs can light up: digitalwrite(latchpin, HIGH); Code Three: Array Introduction */ //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); //Binary notation as comment dataarray[0] = 0xFF; //0b dataarray[1] = 0xFE; //0b dataarray[2] = 0xFC; //0b dataarray[3] = 0xF8; //0b dataarray[4] = 0xF0; //0b dataarray[5] = 0xE0; //0b dataarray[6] = 0xC0; //0b dataarray[7] = 0x80; //0b dataarray[8] = 0x00; //0b dataarray[9] = 0xE0; //0b

6 //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

7 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 % 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 // % it would the code compares it to % // 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

8 //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);