https://docs.google.com/file/d/0B_P7vD_dWeryMWwxSms4cXpCVWc/edit?usp=sharing
C'è anche un integrato nella foto, che nella fattispecie ho scollegato per provare solo la parte di shiftIn, per cui non era collegato al momento delle prove.
Nella seconda foto si vede invece il collegamento dell'IC per lo shiftIn , ovviamente v+ e GND sono collegati giusti anche se non si vedono.
Banalmente ho corretto nel programma anche la il nuero dei pin coinvolti, in quanto li ho cambiati. 10 - Data --- 11 - Clock --- 12 - Latch.
Questo il codice modificato:
//define where your pins are
int latchPin = 12;
int dataPin = 10;
int clockPin = 11;
//Define variables to hold the data
//for shift register.
//starting with a non-zero numbers can help
//troubleshoot
byte switchVar1 = 72; //01001000
//define an array that corresponds to values for each
//of the shift register's pins
char note2sing[] = {
'C', 'd', 'e', 'f', 'g', 'a', 'b', 'c'};
void setup() {
//start serial
Serial.begin(9600);
//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);
//This for-loop steps through the byte
//bit by bit which holds the shift register data
//and if it was high (1) then it prints
//the corresponding location in the array
for (int n=0; n<=7; n++)
{
//so, when n is 3, it compares the bits
//in switchVar1 and the binary number 00001000
//which will only return true if there is a
//1 in that bit (ie that pin) from the shift
//register.
if (switchVar1 & (1 << n) ){
//print the value of the array location
Serial.println(note2sing[n]);
}
}
//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;
}