Variable in der Headerdatei

#include "main.h"

#include "suart.h"

#define BIT_TIME  (u8)((XTAL / BAUD) / PRESCALE)

volatile u8 stx_count;

u8 stx_data;

volatile u8 srx_done;

u8 srx_data;

u8 srx_mask;

u8 srx_tmp;

void suart_init( void )

{

  SBIT(PORTD,STX) = 1;

  // OCR0A = TCNT0 + 1;    // force first compare

  // TCCR0A = 0;        // Default: Normal port operation

  TCCR0B = 1 << CS01 | 1<<CS00;  // clk/64

  // TIFR0 = 1<<ICF1;      // clear pending interrupt

  TIMSK0 = 1 << OCIE0A;    // enable output compare interrupt

  EICRA = 1 << ISC01;      // falling edge

  EIMSK = 1 << INT0;      // enable edge interrupt

  stx_count = 0;        // nothing to sent

  srx_done = 0;            // nothing received

  STXDDR |= 1 << STX;      // TX output

}

u8 sgetchar (void)      // get byte

{

  while (!srx_done);      // wait until byte received

  srx_done = 0;

  return srx_data;

}

ISR (INT0_vect)    // rx start

{

  OCR0B = TCNT0 + (u8)((BIT_TIME * 3) / 2);// scan 1.5 bits after start

  srx_tmp = 0;        // clear bit storage

  srx_mask = 1;        // bit mask

  if( !(SRXPIN & 1<<SRX))  {  // still low

    EIMSK &= ~(1 << INT0);      // disable edge interrupt

    TIMSK0 = 1<<OCIE0A^1<<OCIE0B;  // wait for first bit

}

  TIFR0 = 1<<OCF0B;      // clear pending interrupt ? why does that output compare int occur?

EIFR |= (1 << INTF0);    // clear any pending edge interrupt

}

ISR (TIMER0_COMPB_vect)

{

  u8 in = SRXPIN;      // scan rx line

  // PORTB = 0x00;

  if (srx_mask) {

      if (in & 1 << SRX)

      srx_tmp |= srx_mask;

    srx_mask <<= 1;

    OCR0B += BIT_TIME;      // next bit slice

  } else {

    srx_done = 1;      // mark rx data valid

    srx_data = srx_tmp;      // store rx data

    // TIFR0 = 1<<ICF1;      // clear pending interrupt

    TIMSK0 = 1<<OCIE0A;        // enable tx and wait for start

    EIFR |= (1 << INTF0);    // clear any pending edge interrupt: This hinders the in0-vect from beeing triggerd again just now which may occur by falling edges in the serial data bits

    EIMSK = 1 << INT0;  // reenable edge interrupt

  }

    // PORTB = 0x02;

}

void sputchar (u8 val)      // send byte

{

  while (stx_count);      // until last byte finished

  stx_data = ~val;      // invert data for Stop bit generation

  stx_count = 10;      // 10 bits: Start + data + Stop

}

void sputs (u8 *txt)      // send string

{

  while (*txt)

    sputchar (*txt++);

}

ISR (TIMER0_COMPA_vect)    // tx bit

{

  u8 dout;

  u8 count;

  OCR0A += BIT_TIME;      // next bit slice

  count = stx_count;

  if (count) {

    stx_count = --count;    // count down

    // ??? dout = 1<<COM0A1;      // set low on next compare

    dout = 0;

    if (count != 9) {      // no start bit

      if (!(stx_data & 1))    // test inverted data

        //??? dout = 1<<COM0A1^1<<COM0A0;  // set high on next compare

        dout = 1;

          stx_data >>= 1;      // shift zero in from left

    }

    // TCCR0A = dout;

    // STX = (dout == 0) ? 1 : 0;

    SBIT(PORTD,STX) = dout;

  }

}

#define SRX    PD6

#define SRXPIN  PIND

#define STX    PD5    //Pinbelegung Datasheet (OC1A) #define STX    PD4

#define STXDDR  DDRD

extern volatile u8 srx_done;

#define kbhit()  (srx_done)  // true if byte received

void suart_init( void );

void sputchar( u8 val );

u8 sgetchar( void );

void sputs( u8 *txt );

struct bits {

  u8 b0:1;

  u8 b1:1;

  u8 b2:1;

  u8 b3:1;

  u8 b4:1;

  u8 b5:1;

  u8 b6:1;

  u8 b7:1;

} __attribute__((__packed__));

#define SBIT_(port,pin) ((*(volatile struct bits*)&port).b##pin)

#define  SBIT(x,y)  SBIT_(x,y)

#define SRX1 PD6

#define SRXPIN1  PIND

#define STX1 PD4    //Pinbelegung Datasheet (OC1A) #define STX    PD4

#define STXDDR1  DDRD

extern volatile u8 srx_done1;

#define kbhit()  (srx_done1)  // true if byte received

void suart_init1( void );

void sputchar1( u8 val );

u8 sgetchar1( void );

void sputs1( u8 *txt );

struct bits1 {

  u8 b0:1;

  u8 b1:1;

  u8 b2:1;

  u8 b3:1;

  u8 b4:1;

  u8 b5:1;

  u8 b6:1;

  u8 b7:1;

} __attribute__((__packed__));

#define SBIT_1(port,pin) ((*(volatile struct bits1*)&port).b##pin)

#define  SBIT1(x,y)  SBIT_1(x,y)