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103 lines
2.6 KiB
103 lines
2.6 KiB
/* SevenSegmentLEDdisplay102a.ino
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* 2017-02-20
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* Mel Lester Jr.
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* Simple example of using Shift Register with a
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* Single Digit Seven Segment LED Display
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*/
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// Globals
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const int dataPin = 4; // blue wire to 74HC595 pin 14
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const int latchPin = 7; // green to 74HC595 pin 12
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const int clockPin = 8; // yellow to 74HC595 pin 11
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/* uncomment one of the following lines that describes your display
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* and comment out the line that does not describe your display */
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const char common = 'a'; // common anode
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//const char common = 'c'; // common cathode
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bool decPt = true; // decimal point display flag
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void setup() {
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// initialize I/O pins
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pinMode(dataPin, OUTPUT);
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pinMode(latchPin, OUTPUT);
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pinMode(clockPin, OUTPUT);
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}
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void loop() {
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decPt = !decPt; // display decimal point every other pass through loop
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// generate characters to display for hexidecimal numbers 0 to F
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for (int i = 0; i <= 15; i++) {
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byte bits = myfnNumToBits(i) ;
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if (decPt) {
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bits = bits | B00000001; // add decimal point if needed
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}
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myfnUpdateDisplay(bits); // display alphanumeric digit
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delay(500); // pause for 1/2 second
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}
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}
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void myfnUpdateDisplay(byte eightBits) {
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if (common == 'a') { // using a common anonde display?
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eightBits = eightBits ^ B11111111; // then flip all bits using XOR
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}
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digitalWrite(latchPin, LOW); // prepare shift register for data
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shiftOut(dataPin, clockPin, LSBFIRST, eightBits); // send data
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digitalWrite(latchPin, HIGH); // update display
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}
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byte myfnNumToBits(int someNumber) {
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switch (someNumber) {
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case 0:
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return B11111100;
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break;
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case 1:
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return B01100000;
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break;
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case 2:
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return B11011010;
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break;
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case 3:
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return B11110010;
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break;
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case 4:
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return B01100110;
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break;
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case 5:
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return B10110110;
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break;
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case 6:
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return B10111110;
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break;
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case 7:
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return B11100000;
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break;
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case 8:
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return B11111110;
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break;
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case 9:
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return B11110110;
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break;
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case 10:
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return B11101110; // Hexidecimal A
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break;
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case 11:
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return B00111110; // Hexidecimal B
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break;
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case 12:
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return B10011100; // Hexidecimal C or use for Centigrade
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break;
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case 13:
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return B01111010; // Hexidecimal D
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break;
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case 14:
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return B10011110; // Hexidecimal E
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break;
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case 15:
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return B10001110; // Hexidecimal F or use for Fahrenheit
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break;
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default:
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return B10010010; // Error condition, displays three vertical bars
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break;
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}
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}
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