#include "wiring_private.h"
// Area modulo UART SW usw
#define USWNRXB 32
#define USWNTXB 32
// Tau Baud Rate in TICKS: 833 per 300, 26 per 9600
#define USWBRT 26
#define USWSTA 13
volatile uint8_t uswtmp, uswmask, uswidx, uswbyte[USWNRXB];
volatile uint8_t uswtmr, uswmasr, uswidr, uswfer[USWNRXB/8+1];
volatile uint8_t uswtmt, uswmast, uswidt, uswntx, uswbytt[USWNTXB];
//
void setup() {

  Serial.begin(9600);
// Inizializzazione Area UART usw
  uswidx=uswmask=uswtmp=uswidr = 0;
  uswmasr=1;
  sbi(PCMSK2, PCINT18);
  sbi(PCICR,PCIE2);
  OCR0A=0;
  cbi(TCCR0A, WGM00); // Normal Mode
  cbi(TCCR0A, WGM01); // Normal Mode
  cbi(TCCR0B, WGM02); // Normal Mode
  sbi(TIMSK0, OCIE0A);
  // Output D4 per testing
  sbi(DDRD, 4);
//
  Serial.print("Salve, mondo\n");
  delay(1000);
  Serial.println(F_CPU);
  for(uint8_t i=0; i<uswidx; i++){
    Serial.write(uswbyte[i]);
    uswbytt[i] = uswbyte[i]+1;
    if(uswfer[uswidx >>3] & (1 << uswidx&7))Serial.write('@');
  }
  Serial.write(10); 
// Inizializzatione modulo TX
  sbi(DDRD, 3);   // Tx Pin
  sbi(PORTD, 3);  // Normalmente H
  uswidt = 0;
  uswmast=0xff;
  uswntx = uswidx;
  OCR0B=TCNT0+USWBRT;
  cbi(TIFR0,OCF0B);  
  sbi(TIMSK0, OCIE0B);
  delay(1000);
  while(Serial.available())Serial.write(Serial.read());
}
void loop() {
}
ISR(TIMER0_COMPB_vect){
  if(uswntx) {
sbi(PORTD,4);    
    if(uswmast) {
      if(uswmast == 0xff){
        cbi(PORTD,3);   //Start bit
        OCR0B=TCNT0+USWBRT;
        uswmast=1;
        uswtmt = uswbytt[uswidt];
      } else {
        if(uswtmt & uswmast)sbi(PORTD,3); else cbi(PORTD,3);
        uswmast <<=1;
        OCR0B +=USWBRT;
      }
    } else {
      sbi(PORTD,3);   // Stop bit
      OCR0B +=USWBRT;
      uswntx--; uswidt++;
      uswmast=0xff;
    }
cbi(PORTD,4);    
  } else cbi(TIMSK0, OCIE0B);   // Disable Interrupt
}

ISR(TIMER0_COMPA_vect){
//ISR(TIMER0_COMPA_vect, ISR_NAKED){
  uint8_t mask = uswmask;
  if(mask){
//sbi(PORTD,4);    
    uint8_t tbit = PIND & 0x04; //
    OCR0A +=USWBRT;
    if(mask == 0xff){ // uswfer[uswidx >>3] |= 1 << uswidx&7
      if(tbit == 0) uswtmr |= uswmasr;
      uswmasr <<=1;
      if(uswmasr == 0) {
        if(uswidr < USWNRXB/8+1) uswfer[uswidr++] = uswtmr;
        uswmasr=1;
        uswtmr=0;
      }
      if(uswidx < USWNRXB) uswidx++;
      mask=0;
      sbi(PCMSK2, PCINT18); // Riattiva interrupt su PC
    } else {
      if(tbit) uswtmp |= mask;
      mask <<=1;
      if(mask == 0){
       if(uswidx < USWNRXB) uswbyte[uswidx]=uswtmp;
//       if(uswidx < USWNRXB) *puswbyte++ = uswtmp; // Occupa di più
       mask=0xff;
     }
    }
    uswmask=mask;
//    cbi(PORTD,4);
  };
}
ISR(PCINT2_vect){
  if((PIND & 4) == 0) {
    OCR0A = TCNT0+USWBRT+USWSTA;
    cbi(PCMSK2, PCINT18);
    uswmask = 1;
    uswtmp=0;  
  }
}