CD4021B CMOS 8 Stage Static Shift Registers

Used Products:

1. 8 Position On/Off DIP Switch
2. Arduino UNO
3. CD4021BE
4. LCD LiquidCrystal LCM1602C

Content:

Çeşme: http://www.arduino.cc/en/Tutorial/ShiftIn

Code:

//**************************************************************// // Name : shiftIn Example 1.1 // // Author : Carlyn Maw // // Date : 25 Jan, 2007 // // Version : 1.0 // // Notes : Code for using a CD4021B Shift Register // // : // //**************************************************************** #include <LiquidCrystal.h> LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //define where your pins are int latchPin = 8; int dataPin = 9; int clockPin = 7; //Define variables to hold the data //for shift register. //starting with a non-zero numbers can help //troubleshoot byte switchVar1 = 72; //01001000 void setup() { //start serial Serial.begin(9600); lcd.begin(16, 2); //define pin modes pinMode(latchPin, OUTPUT); pinMode(clockPin, OUTPUT); pinMode(dataPin, INPUT); } void loop() { //Pulse the latch pin: //set it to 1 to collect parallel data digitalWrite(latchPin,1); //set it to 1 to collect parallel data, wait delayMicroseconds(20); //set it to 0 to transmit data serially digitalWrite(latchPin,0); //while the shift register is in serial mode //collect each shift register into a byte //the register attached to the chip comes in first switchVar1 = shiftIn(dataPin, clockPin); //Print out the results. //leading 0's at the top of the byte //(7, 6, 5, etc) will be dropped before //the first pin that has a high input //reading Serial.println(switchVar1, BIN); lcd.clear(); lcd.setCursor(0, 0); lcd.print("DEC: "+String(switchVar1)); lcd.setCursor(0, 1); lcd.print("BIN: "+String(switchVar1, BIN)); //white space Serial.println("-------------------"); //delay so all these print satements can keep up. delay(500); } //------------------------------------------------end main loop ////// ----------------------------------------shiftIn function ///// just needs the location of the data pin and the clock pin ///// it returns a byte with each bit in the byte corresponding ///// to a pin on the shift register. leftBit 7 = Pin 7 / Bit 0= Pin 0 byte shiftIn(int myDataPin, int myClockPin) { int i; int temp = 0; int pinState; byte myDataIn = 0; pinMode(myClockPin, OUTPUT); pinMode(myDataPin, INPUT); //we will be holding the clock pin high 8 times (0,..,7) at the //end of each time through the for loop //at the begining of each loop when we set the clock low, it will //be doing the necessary low to high drop to cause the shift //register's DataPin to change state based on the value //of the next bit in its serial information flow. //The register transmits the information about the pins from pin 7 to pin 0 //so that is why our function counts down for (i=7; i>=0; i--) { digitalWrite(myClockPin, 0); delayMicroseconds(0.2); temp = digitalRead(myDataPin); if (temp) { pinState = 1; //set the bit to 0 no matter what myDataIn = myDataIn | (1 << i); } else { //turn it off -- only necessary for debuging //print statement since myDataIn starts as 0 pinState = 0; } //Debuging print statements //Serial.print(pinState); //Serial.print(" "); //Serial.println (dataIn, BIN); digitalWrite(myClockPin, 1); } //debuging print statements whitespace //Serial.println(); //Serial.println(myDataIn, BIN); return myDataIn; }