/////////////////////////////////////////////////////////////////////////////
////             i2c_graphic_primitive.C   
//      PIC program to allow Slug to send primitive graphic
//        display commands to a 64 x 128 graphic display
//
//    the PIC sends this string of data for pic_buf[]
//    pic_buf[0] contains command codes as below:-
//    x=0, y=0 is the top left corner
//
// 1 line(x1 y1 x2 y2 color(0/1))
// 2 rectangle (x1 y1 x2 y2 fill(0/1) color(0/1)
// 3 bar(x1 y1 x2 y2 width color(0/1) - - - fails, why?
// 4 circle(x y radius fill(0/1) color(0/1))
// 5 text to screen (x y ASCIIasDecimal size color(0/1)) -e.g. send 65 for A
// 6 pixel (x y color(0/1))
// 7 wipe all screen to black or white (color(0/1))
//////////////////////////////////////////////////////////////////////////////

#include <16F877.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use i2c(SLAVE, SDA=PIN_C4, SCL=PIN_C3, address=0xA2, FORCE_HW)
 //A0 is 80 in Linux decimal, A2 is 81 (as seen in i2cdetect 0)
#include <HDM64GS12.c>
#include <graphics.c>
#include <math.h>

BYTE state; // receive string of up to 127 bytes on the i2c line
int8 pic_buf[10]; //the i2c data from the Slug go in here
int i; //for counts
char screen_text[1]; //real character then null character

//===========================================================i2c interrupt routine
#INT_SSP
void ssp_interupt ()
{
  state = i2c_isr_state();
  //i2c event caused by i2c master interrups the PIC
  //"state" sets if the master is requesting or sending data
  if(state < 0x80) //Master is sending data
   {
     if(state == 0) 
     {
     }  
   }
     for(i=0; i<=7; ++i) 
      {
      if(state == (i+1))  // state increments from 1 as each data byte comes in
        {
          pic_buf[i] = i2c_read();
        }
      }
  if(state == 0x80)  //Master is requesting data from the PIC
   {
   i2c_write (10);//dummy response - i2cdetect fails without this -why !?!?
   }
}
//============================================================i2c end of interrupt


//*****************************************************************************main
void main() {

char string_1[] = "Welcome!";
char string_2[] = "Waiting for i2c data";
  enable_interrupts(INT_SSP);
  enable_interrupts(GLOBAL);
  glcd_init(ON);                               // Must initialize the LCD
  
  glcd_fillScreen(0); //screen all black
  glcd_text57(20, 16, string_1, 2, 1);
  glcd_text57(4, 45, string_2, 1, 1);
  delay_ms(20);
   for(;;) //repeat for ever
   {
   
   // ------------------------------------------------------------------------line
  if ((pic_buf[0]==1)) 
  {
   glcd_line(pic_buf[1], pic_buf[2], pic_buf[3], pic_buf[4], pic_buf[5]); 
  } 
    // ----------------------------------------------------------------------rectangle 
  if ((pic_buf[0]==2)) 
  {
   glcd_rect(pic_buf[1], pic_buf[2], pic_buf[3], pic_buf[4], pic_buf[5], pic_buf[6]); 
  }
   // -------------------------------------------------------------------bar (fails!!)
  if ((pic_buf[0]==3))
  {
   glcd_bar(pic_buf[1], pic_buf[2], pic_buf[3], pic_buf[4], pic_buf[5], pic_buf[6]); 
  }
  // --------------------------------------------------------------------------circle
  if ((pic_buf[0]==4)) 
  {
   glcd_circle(pic_buf[1], pic_buf[2], pic_buf[3], pic_buf[4], pic_buf[5]); 
  }
  // ------------------------------------------------------------------ text to screen
  if ((pic_buf[0]==5))
  {
  sprintf(screen_text,"%c",pic_buf[3]);
  glcd_text57(pic_buf[1], pic_buf[2], screen_text, pic_buf[4], pic_buf[5]); 
  }
   // ------------------------------------------------------------------------ pixel
  if ((pic_buf[0]==6))
  {
   glcd_pixel(pic_buf[1], pic_buf[2], pic_buf[3]); 
  }
   // --------------------------------------------------------------------wipe screen
  if ((pic_buf[0]==7))
  {
   glcd_fillScreen(pic_buf[1]); 
  }
//  else
// {
//  pic_buf[0]=10 ;
//  }

  
  
// flash the top left pixel to show program alive
   glcd_rect(0, 0, 0, 0, YES, ON);
   delay_ms(300); 
   glcd_rect(0, 0, 0, 0, YES, OFF);
   delay_ms(300);
}
}