/* ********************************************************************** 
 * ## Ready to build ##
 * ATTiny85_7Seg_DHT22
 * 7-SegmentDisplay - v1.0
 *  Uses (2) Common cathode 7-segment display,
 *  Uses (2) 74HC595 shift register IC
 *  Uses ATTiny85
 *
 * Description:
 *  This sketch illustrates the controlling of two 7-segment displays with
 *  two 74HC595 shift register. Charlieplexing is not used. Daisychained
 *  shift registers push 8 bits at a time from one display to the next.
 *  For a two digit display this is quite easy to code.
 
 *  Sketch uses 5236 bytes (63%) of program storage space. Maximum is 8192 bytes.
 *  Global variables use 80 bytes (15%) of dynamic memory, leaving 432 bytes for local variables. Maximum is 512 bytes.
 *   
 * See spreadsheet file 74HC595_SegmentDisplay.ods
 * Define the LED digit patterns, from 0 - 9
 * 1 = LED on, 0 = LED off, common cathode, in this order:
 *           74HC595 pin     Q7,Q6,Q5,Q4,Q3,Q2,Q1,Q0 
 *           Mapping to      dp,g,f,e,d,c,b,a of Seven-Segment LED
 * ********************************************************* */

#include <TinyDebug.h>

/********** Hardware Definitions **********/
int latchPin = PB0; // connect to the ST_CP of 74HC595 (pin 12,latch pin)
int dataPin = PB1; // connect to the DS of 74HC595 (pin 14, data pin)
int clockPin = PB2; // connect to the SH_CP of 74HC595 (pin 11, clock pin)


byte digits[10] = { B11111100,  // = 0
                    B00110000,  // = 1
                    B11011010,  // = 2
                    B01111010,  // = 3
                    B00110110,  // = 4
                    B01101110,  // = 5
                    B11100110,  // = 6
                    B00111000,  // = 7
                    B11111110,  // = 8
                    B00111110   // = 9
};


byte sevenSegDP = B00000001;  // = DP

/*---------- Function Declaration ----------*/

void writeDigits(byte r1, byte r2);
void writeSegment(byte segment);
void writeBlank();


void setup() {
  Debug.begin();

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

void loop() {

//*
  // count to 99
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < 10; j++) {
      // First 8 bytes 'j' goes into register 1.
      // Second 8 bytes 'i' goes into register 1 and pushes first 8 bytes into register 2.
      writeDigits(i, j);
      delay(500);
    }
  }
//*/

/*
  writeDigits(5, 2); // write humid to 7-Segments
  delay(2000);
  writeDigits(8, 0);
  delay(2000);
*/

//*
  writeSegment(B11111111); // write temp to 7-Segments
  delay(2000);
  writeSegment(B00000000);
  delay(2000);
//*/


  Debug.print("7Seg1: "); Debug.println(digits[0], BIN);
  Debug.print("7Seg2: "); Debug.println(digits[1], BIN);

} // end of void loop


/*---------- Functions ----------*/

// display a alpha, binary value, or number on the digital segment display
void writeDigits(byte r1, byte r2) {
  // r1, r2 = array pointer or binary value, as a byte 
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, digits[r2]);
  shiftOut(dataPin, clockPin, MSBFIRST, digits[r1]);
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}

void writeSegment(byte segment) {
  // segment = array pointer or binary value, as a byte 
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, segment);
  shiftOut(dataPin, clockPin, MSBFIRST, segment);
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}


void writeBlank() {
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, B00000000);
  shiftOut(dataPin, clockPin, MSBFIRST, B00000000);
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}