/*****************************************************************************************************/
/* R U T I N E _ Z A _ K O M U N I K A C I J O _ P R E K O _ 
   D A L L A S _ 1 _ W I R E _ V O D I L A */
/*****************************************************************************************************/
//npr. #define	TOUCH_PIN	PIN_C7	//mora biti izhod,uporabi FAST_IO()

/* 
spremenjen 1998-12-30 da dela tudi ob vkljuŸenem IRQ, 
IRQ mora biti na 256 us in brisati bit "cakaj_irq"
sedaj dela pri FAST_IO
vkljuŸena tudi CRC iz read_key-[Branko Premzel]
*/
#define	PORT_ADDR(pin)	((unsigned)(pin)/8) /*iz çtevilke pina izr.naslov porta*/
#define	PORT_BIT(pin)	((pin)-PORT_ADDR(pin)*8) /*izr. stevilko bita na portu*/
/*npr	bit_set(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); 
postavi TRIS bit od TUCH_PINa*/

//////////////////////////////////////////////////////////////////////////
////                        Dallas Touch Driver                       ////
////                                                                  ////
////  present = touch_present()   Issues a reset and returns TRUE     ////
////                              if the touch device is there.       ////
////                                                                  ////
////  data = touch_read_byte()    Reads one byte from a touch device. ////
////                                                                  ////
////  ok = touch_write_byte(data) Writes one byte to a touch device   ////
////                              and returns TRUE if all went OK.    ////
////                              A FALSE indicates a collision with  ////
////                              another device.                     ////
////                                                                  ////
//////////////////////////////////////////////////////////////////////////
////        (C) Copyright 1996,1997 Custom Computer Services            ////
//// This source code may only be used by licensed users of the CCS C   ////
//// compiler.  This source code may only be distributed to other       ////
//// licensed users of the CCS C compiler.  No other use, reproduction  ////
//// or distribution is permitted without written permission.           ////
//// Derivative programs created using this software in object code     ////
//// form are not restricted in any way.                                ////
////////////////////////////////////////////////////////////////////////////

#ifndef TOUCH_PIN
#error ***** TOUCH_PIN ni doloŸen !!!!!
#define TOUCH_PIN  PIN_B0
//#bit    TOUCH_PIN_BIT = 6.0 //ni potrebno; nadomeçŸeno z input(TOUCH_PIN)
#endif


BYTE touch_read_byte(void) {
   BYTE i,data;
   BOOLEAN rx_bit;
   for(i=1;i<=8;++i) {
     disable_interrupts(GLOBAL);  // OnemogoŸi prekinitve 
     bit_clear(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //zbriçe TRIS bit,da ni problema pri FAST_IO
     output_low(TOUCH_PIN);
//     delay_us(14);
     delay_us(10);  //14us je bilo vŸasih predolgo in ni pravilno bral
//     output_float(TOUCH_PIN);
     bit_set(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //postavi TRIS bit da ni problema pri FAST_IO
     delay_us(5);
     rx_bit = input(TOUCH_PIN);
     shift_right(&data,1,rx_bit);
     enable_interrupts(GLOBAL);  // OmogoŸi prekinitve
//******** CRC ******
      if ((CRC_vsota ^ rx_bit) & 1)
	CRC_vsota = ((CRC_vsota ^ 0x18) >> 1) | 0x80;
      else
	CRC_vsota >>= 1;
//*******************
     delay_us(100); //pavza med biti ni Ÿasovno kritiŸna zato so dovoljeni IRQji
   }
   return(data);
}

BYTE touch_write_byte(BYTE data) {
   BYTE i;
   bit_clear(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //zbriçe TRIS bit,da ni problema pri FAST_IO
   for(i=1;i<=8;++i) {
     disable_interrupts(GLOBAL);  // OnemogoŸi prekinitve 
     output_low(TOUCH_PIN);
     delay_us(5);
     if(shift_right(&data,1,0)) {
       output_high(TOUCH_PIN);
//brez veze     bit_set(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //postavi TRIS bit da ni problema pri FAST_IO
//       if(!TOUCH_PIN_BIT)
       if(!input(TOUCH_PIN))
          goto exit_write_ret_0;
     } else {
       output_low(TOUCH_PIN);
//       if(TOUCH_PIN_BIT)
       if(input(TOUCH_PIN))
          goto exit_write_ret_0;
     }
     delay_us(55);
     output_high(TOUCH_PIN);
     enable_interrupts(GLOBAL);  // OmogoŸi prekinitve
     delay_us(50);  //pavza med biti ni Ÿasovno kritiŸna zato so dovoljeni IRQji
   }
   return(TRUE);
exit_write_ret_0:
   enable_interrupts(GLOBAL);  // OmogoŸi prekinitve
   return(0);
}

BYTE touch_present() {
    BOOLEAN present = 0; //da ob napaki vrne FALSE
#ifdef DELAY_IRQJEV
    Delay_irqjev(1);   //poŸaka na konec prvega irq 	
#endif
    output_low(TOUCH_PIN);
    bit_clear(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //zbriçe TRIS bit,da ni problema pri FAST_IO
#ifdef DELAY_IRQJEV
    Delay_irqjev(2); //500us ;med irq-ji je 256us
#else
    delay_us(500);
#endif
    disable_interrupts(GLOBAL);  // OnemogoŸi prekinitve 
//    output_float(TOUCH_PIN);
    bit_set(*(PORT_ADDR(TOUCH_PIN)+0x80),PORT_BIT(TOUCH_PIN)); //postavi TRIS bit da ni problema pri FAST_IO
    delay_us(8);
    if(!input(TOUCH_PIN)) 
         goto exit_present_ret_false; //present je nastavljen na 0
    delay_us(100);
    present=!input(TOUCH_PIN);
exit_present_ret_false:
    enable_interrupts(GLOBAL);  // OmogoŸi prekinitve
    delay_us(240);
    if(present)
      return(TRUE);
    else
      return(FALSE);
}