/////////////////////////////////////////////////////////////////////////////
////        i2c_graphicLCD_2.C derived from EX_GLCD.C   
// PIC program to display data point in an area of any width
//  data given to master program PIC_i2c_send_data_to_plot_ram comes here
//  first 8 bytes stored in pic_buf[60] are commands
// pic_buf[0] = PIC display starting point on x axis
// pic_buf[1] = number of data points sent to be displayed
// pic_buf[2] = 1 - wipe this data area  before plot
// pic_buf[3] = 1 - we WILL plot some data points (0 - just switch lines later)
// pic_buf[4] = 1 - wipe whole screen
// pic_buf[5] = 0 - free
// pic_buf[6] = 0 - free
// pic_buf[7] = 0 - free
//
// then this program receives data from a file in the ramdisk folder
// from a single data point to a string of 50
//////////////////////////////////////////////////////////////////////////////


#include <16F877.h>
#device ADC=16
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
//#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) - for later
#use i2c(SLAVE, SDA=PIN_C4, SCL=PIN_C3, address=0xA2, FORCE_HW)
 //0xA1 in address is the same as A0 in Linux decimal (it is 80)!!! - step in 2s
 //I2C by Hardware,i2c address (0xA2 is dec 81)is the first byte from the master
#include <HDM64GS12.c>
#include <graphics.c>
#include <math.h>

//#define GP3 PIN_B3 -for later
//#define GP4 PIN_B6
//#define GP5 PIN_B7

BYTE incoming, state; // receive string of up to 127 bytes on the i2c line
int8 pic_buf[60]; //can't be much bigger
int8 i;//for a count
int8 k;//for a count


//====================================================================i2c 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<=60; ++i) 
      {
      if(state == (i+1))  // state increments from 1 as each data byte comes in
        {
          incoming = i2c_read();
          pic_buf[i] = incoming;
        }
      }
  if(state == 0x80)  //Master is requesting data from the PIC
   {
   i2c_write (10);//dummy response - i2cdetect fails without this -why !?!?
   }
}

//============================================================i2c end of interrupt
void displayVoltage(int plot) //old code adapted to show commands
{
   char voltage[9];
//   sprintf(voltage, "%f", (float)plot); // Converts plot to text
   sprintf(voltage, "%d", (int)plot); // Converts plot to text
   voltage[4] = '\0';                              // Limit shown digits to 3
    glcd_rect(106, 0, 131, 7, YES, OFF);           // Clear the old voltage
    glcd_text57(106, 0, voltage, 1, ON);           // Write the new voltage
}
//--------------------------------------------------------------------------main
void main() {
 int8 plot = 0;

  enable_interrupts(INT_SSP);
  enable_interrupts(GLOBAL);

k = 0;// scan the command numbers on the screen

   glcd_init(ON);                               // Must initialize the LCD

   for(;;) {
 if (pic_buf[4]==1)//clear screen
  {
  glcd_fillScreen(OFF);
  }
  pic_buf[4]=0;// only clear screen once per command session
  
      plot = pic_buf[k] ;
     displayVoltage(plot);                      // Display the reading

 
 if (pic_buf[2]==1)//wipe local
     {
     glcd_rect((pic_buf[0]), 63, (pic_buf[0]+ pic_buf[1] - 1), 0, YES, OFF) ;
     }
     pic_buf[2]=0;// only wipe once per command session
     
 if (pic_buf[3]==1)//plot the pic_buf[1] points
    {
    for (i=0; i<pic_buf[1]; i=i+1)
      {
       glcd_pixel((i+pic_buf[0]),(63 - pic_buf[i+8]/4),ON) ;//plot all but the first 8 pic_buf values
      }
    }
    pic_buf[3]=0; // only plot the set once per command session
      delay_ms(1000);    // Reduces flicker
                        // lets you read the command numbers
k = k + 1 ;
if (k == 8) //show the command numbers in the top RH corner
  {
  k = 0;
  }
}  
}