Lesson 27 74HC595 And SegmentDisplay

byte seven_seg_digits[10] = { B11111100, // = 0
B01100000, // = 1
B11011010, // = 2
B11110010, // = 3
B01100110, // = 4
B10110110, // = 5
B10111110, // = 6
B11100000, // = 7
B11111110, // = 8
B11100110 // = 9
};

// connect to the ST_CP of 74HC595 (pin 3,latch pin)
int latchPin = 3;
// connect to the SH_CP of 74HC595 (pin 4, clock pin)
int clockPin = 4;
// connect to the DS of 74HC595 (pin 2)
int dataPin = 2;

void setup() {
// Set latchPin, clockPin, dataPin as output
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
}

// display a number on the digital segment display
void sevenSegWrite(byte digit) {
// set the latchPin to low potential, before sending data
digitalWrite(latchPin, LOW);

// the original data (bit pattern)
shiftOut(dataPin, clockPin, LSBFIRST, seven_seg_digits[digit]);

// set the latchPin to high potential, after sending data
digitalWrite(latchPin, HIGH);
}

void loop() {
// count from 9 to 0
for (byte digit = 10; digit > 0; –digit) {
delay(1000);
sevenSegWrite(digit – 1);
}

// suspend 4 seconds
delay(3000);
}