/* ******************************************************************************************
 * Program ID: Arduino_I2C_Device.pde
 * Created by: CH, Chen (Taiwan) 2011.8.28
 *
 * ****************************************************************************************** */
#include "Wire.h"

#define THIS_DEVICE                0x31

#define COMMAND_DEVICE_INFO        0x00
#define COMMAND_DISPLAY_NUMBER     0x42
#define COMMAND_DISPLAY_TEXT       0x43

#define SEVEN_SEG_LED              0x38
#define THERMOMETER                0x49
#define RED_LED                    3
#define GREEN_LED                  5
#define BLUE_LED                   6

#define NUM_OF_DIGITS              4
#define MAX_TEXT_LENGTH            16

uint8_t deviceInfo[9] = "UNO-0x31";

// Seven segment display pattern: 
// Numberals                   0,    1,    2,    3,    4,    5,    6,    7,    8,    9,    blank,-
const byte NumPattern[12]   = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D ,0x07, 0x7F, 0x6F, 0x00, 0x40};
// Alphabet                    A,    b,    C,    d     E     F     G     H     I     J     K     L     M
//                             n     O     P     q     r     s     T     U     v     W     X     y     Z
const byte AlphaPattern[26] = {0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71, 0x3D, 0x76, 0x06, 0x1E, 0x7A, 0x38, 0x15,
                               0x54, 0x3F, 0x73, 0x67, 0x31, 0x6D, 0x07, 0x3E, 0x1C, 0x2A, 0x49, 0x6E, 0x52};
const byte BlankPattern     =  0x00;
const byte DotPattern       =  0x80;
byte requestRegister;
int  receiveNumber;
char ReceiveText[MAX_TEXT_LENGTH];
boolean isDisplayNumber, isDisplayText;

void setup()
{
  Serial.begin(9600);
  pinMode(RED_LED,   OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(BLUE_LED,  OUTPUT);
  digitalWrite(RED_LED,   HIGH);
  digitalWrite(GREEN_LED, LOW);
  digitalWrite(BLUE_LED,  LOW);
  
  // Join I2C bus as Master
  Wire.begin();  
  // Initialize SAA1064 7-Segment LED driver (0x38)
  Wire.beginTransmission(SEVEN_SEG_LED);
  Wire.send(B00000000);    // Instruction byte, the next byte is the control byte
  Wire.send(B01000111);    // Control byte, dynamic mode on, digits 1+3 on, digits 2+4 on, 12mA segment current
  Wire.endTransmission();
  
  // Initialize digital Thermometer (0x49)
  Wire.beginTransmission(THERMOMETER);    
  Wire.send(1);           // Set TMP75 pointer register to configuration register
  Wire.send(B01100000);   // Set TMP75 12 bits resolution(R1,R0)=(0,0), b6,b5 of configuration register
  Wire.endTransmission();
  
  Wire.beginTransmission(THERMOMETER);    
  Wire.send(0);           // Set TMP75 pointer register to temperature register
  Wire.endTransmission(); 
  
  delay(1000);
  // Join I2C bus as slave  
  Wire.begin(THIS_DEVICE);
  Wire.onReceive(receiveEvent);    
  Wire.onRequest(requestEvent);
  
  digitalWrite(RED_LED,   LOW);
  digitalWrite(GREEN_LED, HIGH);
}

void loop()
{
  if (isDisplayNumber) {
      displayInteger(receiveNumber);
      isDisplayNumber = false;
      } 
      else if (isDisplayText) {
               displayString(ReceiveText);
               isDisplayText = false;
           }
}

void receiveEvent(int howMany)
{  
  requestRegister = Wire.receive();
  if (requestRegister == COMMAND_DISPLAY_NUMBER) {
     byte receiveSign = Wire.receive();
     receiveNumber    = Wire.receive();
     if (receiveSign == 0) receiveNumber *= (-1);
     isDisplayNumber  = true;       
  }
  else if (requestRegister == COMMAND_DISPLAY_TEXT) {
           int nbytesReady = Wire.available();
           if (nbytesReady > 0) {
              for (int xcnt=0; xcnt<MAX_TEXT_LENGTH; xcnt++) {
                  if (xcnt < nbytesReady) ReceiveText[xcnt] = (char)Wire.receive();
                  else                    ReceiveText[xcnt] = '@';
              }
              isDisplayText = true;
           }
        }
}

void requestEvent() 
{ 
    if (requestRegister == COMMAND_DEVICE_INFO) {
       Wire.send(deviceInfo, 8);
    }
}

void clearDisplay()
{
  Wire.beginTransmission(SEVEN_SEG_LED);
  Wire.send(1); // Write sub-address, point to register of the 1st digit(Right Hand Side)
  Wire.send(BlankPattern); // blank digit 1
  Wire.send(BlankPattern); // blank digit 2
  Wire.send(BlankPattern); // blank digit 3
  Wire.send(BlankPattern); // blank digit 4
  Wire.endTransmission();
}

// Display at most 4 digits number on LED
// Enable display negative sign
void displayInteger(int intNumber)
{
  int digitSign, digit, digitTen, digitHundred, digitThousand;
  clearDisplay();
 
  digitSign = (intNumber<0 ? 11: 10);
  digitThousand = abs(intNumber)/1000;
  digitHundred = (abs(intNumber) - digitThousand*1000) / 100;
  digitTen = (abs(intNumber) - digitThousand*1000 - digitHundred*100) / 10;
  digit = abs(intNumber) - digitThousand*1000 - digitHundred*100 - digitTen*10;
  if (digitThousand == 0) {
      digitThousand = 10;
      if (digitHundred == 0) {
          digitHundred = 10;
          if (digitTen == 0)  
              digitTen = 10;      
      }
  }
  // Set sign symbol
  if (intNumber < 0) {
      if (digit != 10) {
          if (digitTen != 10) {
              if (digitHundred != 10) 
                  digitThousand = 11;
              else
                  digitHundred  = 11;
          }
          else 
              digitTen = 11;
      }
  }
  Wire.beginTransmission(SEVEN_SEG_LED);
  Wire.send(0x01);  // Write sub-address, point to register of the 1st digit(Right Hand Side)
  Wire.send(NumPattern[digit]);
  Wire.send(NumPattern[digitTen]);
  Wire.send(NumPattern[digitHundred]);
  Wire.send(NumPattern[digitThousand]);  
  Wire.endTransmission();
  delay(1000);   
}

// Display character array/string on LED 
// This function will convert ascii value to pattern then use displayFlyFromRightSide() function
// to display.
void displayString(char displayStr[])
{
  byte displayPattern [strlen(displayStr)];
  int numOfBytes = 0;
  for (int xii=0; xii<strlen(displayStr); xii++)
  { 
    if (displayStr[xii] >= 'A' && displayStr[xii] <= 'Z') {
        displayPattern[numOfBytes] = AlphaPattern[displayStr[xii] - 'A'];
        numOfBytes++;
    }
    else if (displayStr[xii] >= 'a' && displayStr[xii] <= 'z') {            
             displayPattern[numOfBytes] = AlphaPattern[displayStr[xii] - 'a'];
             numOfBytes++;
         }
         else if (displayStr[xii] >= '0' && displayStr[xii] <= '9') {            
                  displayPattern[numOfBytes] = NumPattern[displayStr[xii] - '0'];
                  numOfBytes++;
              }
              else if (displayStr[xii] == ' ') {
                       displayPattern[numOfBytes] = NumPattern[10];
                       numOfBytes++;
                   }
                   else if (displayStr[xii] == '-') {
                            displayPattern[numOfBytes] = NumPattern[11];
                            numOfBytes++;
                        }
                        else if (displayStr[xii] == '.') {
                                 displayPattern[numOfBytes] = DotPattern;
                                 numOfBytes++;
                             }
  }
  if (numOfBytes > 0) displayFlyFromRightSide(displayPattern, numOfBytes);
}

// Display pattern array with fly-in effect
void displayFlyFromRightSide(const byte displayArray[], int numberOfBytes)
{
  int xindex = 0;
  clearDisplay();
  while (xindex < numberOfBytes+NUM_OF_DIGITS)
  {
    Wire.beginTransmission(SEVEN_SEG_LED);
    Wire.send(0x01);  // Write sub-address, point to register of the 1st digit(Right Hand Side)
    for (int xdigit=0, xdisplayIdx=xindex; xdigit<NUM_OF_DIGITS && xdisplayIdx>=0; xdigit++, xdisplayIdx--)
    {    
      if (xdisplayIdx < numberOfBytes) Wire.send(displayArray[xdisplayIdx]);                  
      else                             Wire.send(BlankPattern);         
    }
    Wire.endTransmission();
    delay(600);
    xindex++;
  }  
}