arduino_iic.c

//MASTER BMP DECODER
//Requests data from slave (2bytes)

#include <Wire.h>
#include <TFT.h>
#define SLAVE 0x02

#define YP A2   // must be an analog pin, use "An" notation!
#define XM A1   // must be an analog pin, use "An" notation!
#define YM 14   // can be a digital pin, this is A0
#define XP 17   // can be a digital pin, this is A3 

int x = 0;
int y = 0;
int decode = 1;

void setup(void){
  Serial.begin(9600);
  Wire.begin();
  Tft.init();
}

void loop(void){
  if(decode == 1){
   photo_bytes();
   
  }else{
    change_photo();
    decode = 1;
  }
}

void change_photo(){
  Wire.beginTransmission(SLAVE);
  Wire.write(2);
  Wire.endTransmission();
}

void photo_bytes(){
  Wire.requestFrom(SLAVE,3);
  delay(1);
  while(Wire.available() && decode){
    Serial.println(Wire.available());
    unsigned int color_low = Wire.read();
    unsigned int color_high = Wire.read();
   Serial.print(" - ");
    Serial.print(color_high);
    Serial.print(" - ");
    Serial.println(color_low);
    //color_high = (color_high<<8);
    color_high += color_low;
    Tft.setPixel(x,y,color_high);
    x++;
    if(x == 241){
      x = 0;
      y++;
      if(y == 321){
        y = 0;
        decode = 0;
      }
    }
    //Wire.requestFrom(SLAVE,2); //maakt proces veeeeel sneller
    delay(1);
  }
}

//slave
//Decodes 24 bit bmp to 16 bit colors (hence the 2 bytes)
//Every request is a pixel

#include <SD.h>
#include <Wire.h>

#define SLAVE 0x02
#define RGB16(red, green, blue) ( ((red >> 3) << 11) | ((green >> 2) << 5) | (blue >> 3))

void(* resetFunc) (void) = 0;

unsigned char blue,green,red,color_high,color_low;
unsigned int color;
int no_pics; //aantal fotos
int no_off_pic = 0; //stand van de foto
File pic;

void setup(){
  Serial.begin(9600);
  Serial.println("begin");
  pinMode(13,OUTPUT);  //nodig voor SD kaart
  if (! SD.begin(10)){
    Serial.println("init SD failed\nREBOOT\n--------");
    delay(40);
    resetFunc();
  }
  Serial.println("jep");
  pinMode(13, OUTPUT); //COMMUNICATIE LED
  //picture
  no_pics = listpics(); //tel alle bmp files in /pictures en delete alle niet bmp's
  openpic();            //open eerste foto
  //i²c communicatie
  Wire.onRequest(requestEvent);
  Wire.onReceive(receiveEvent);
  Wire.begin(SLAVE);

}

void loop(void){
  int i = 0;
  i++;
  i = i + i;
  if(i > 200) i = 0;
  if(i < 0) Serial.println("jaja");
}

int readfile(){
  pic.seek(54);
}

int listpics(){
  File dir = SD.open("/pictures");
  int files = 0;
  int lengte;
  char name[255];
  while(1){
    File entry = dir.openNextFile(); //open volgende file
    if(! entry) break; //geen files meer
    strcpy(name," ");
    strcpy(name,entry.name());
    lengte = strlen(name);
    if(name[lengte-1] == 'P' && name[lengte-2] == 'M' && name[lengte-3] == 'B' && name[lengte-4] == '.'){
      files++;
    }
    else{ //delete niet ".bmp" files :D
      strcpy(name,"/pictures/");
      strcat(name,entry.name());
      SD.remove(name);
    }
  }
  return files;
}

void openpic(){
  File dir = SD.open("/pictures");
  char name[255] = "/pictures/";
  int i;
  for(i = 0; i < no_off_pic+1;i++){
    pic = dir.openNextFile();
  }
  strcat(name,pic.name());
  pic = SD.open(name, FILE_READ);
  pic.seek(54);
}

void requestEvent(){
  
  digitalWrite(13, HIGH);   // set the LED on
  if(pic.position() <= pic.size()){
    blue = pic.read();
    green = pic.read();
    red = pic.read();
    color = RGB16(red,green,blue);
    color=0x55AA;
    Wire.write(lowByte(color));
    Wire.write(highByte(color));
  }
  else{
    Serial.println("Error");
  }
  digitalWrite(13, LOW);
}

void receiveEvent(int numBytes){
  int c = Wire.read();
  Serial.write(c);
  if(c == 2){
    no_off_pic++;
    if(no_off_pic > no_pics) no_off_pic = 1;
  }else if(c == 3){
    no_off_pic--;
    if(no_off_pic < 1) no_off_pic = no_pics;
  }
  openpic();
}