#define CAL 62502; //62499 = 1 sec 
#define LED 1
#include <Wire.h> 
#include <OLED_I2C.h>           // http://rcl-radio.ru/wp-content/uploads/2022/01/OLED_I2C.zip

  OLED  myOLED(SDA, SCL, 8);
  extern uint8_t SmallFont[],BigNumbers[];
  unsigned long f_out,tic,n;
 
void setup(){
  PORTD |= (1 << PD5); // подтягивающий резистор на PD5 (вход T1)
  DDRB |= (1 << PB3); // D11 OUTPUT 8 MHz
  delay(200);
  noInterrupts();
// TIMER_1 INPUT T1
  TCCR1A = 0;TCCR1B = 0;TCNT1=0;
  TCCR1B = (1 << CS12) | (1 << CS11) | (1 << CS10);
  TIMSK1 = (1 << TOIE1);
  TCKCSR = (1 << F2XEN) | (1 << TC2XS1);
// TIMER_3 1 SEC
  TCCR3A = 0;
  TCCR3B = 0;
  TCNT3=0;
  TCCR3B = (1 << CS32) | (1 << WGM32);
  TIMSK3 = (1 << OCIE3A);
  OCR3A = CAL;
// TIMER_2 OUTPUT 8 MHz
TCCR2A = 0;TCCR2B = 0;TCNT2=0;
  TCCR2A = 1 << COM2A0 |1 << WGM21;
  TCCR2B = 1 << CS20;
  OCR2A = 0;
  interrupts();
  Wire.begin();
  myOLED.begin();
  myOLED.setBrightness(100);
  myOLED.clrScr();
  myOLED.update();
  delay(1000);
  }

void loop(){
  myOLED.clrScr();
  myOLED.setFont(BigNumbers);
if(f_out>=10000000)  myOLED.printNumI(f_out/10000000%10, 0, 35);
if(f_out>=1000000)  myOLED.printNumI(f_out/1000000%10, 15, 35);
if(f_out>=100000)  myOLED.printNumI(f_out/100000%10, 35, 35);
if(f_out>=10000)  myOLED.printNumI(f_out/10000%10, 50, 35);
if(f_out>=1000)  myOLED.printNumI(f_out/1000%10, 65, 35);
if(f_out>=100)  myOLED.printNumI(f_out/100%10, 85, 35);
if(f_out>=10)  myOLED.printNumI(f_out/10%10, 100, 35);
  myOLED.printNumI(f_out/1%10, 115, 35);
  myOLED.update();
  delay(1000);
  if(LED==1){
  if(f_out==0){n++;}else{n=0;}
  if(n>=10){myOLED.setBrightness(0);}else{myOLED.setBrightness(100);}
  }else{myOLED.setBrightness(100);}
  }

ISR(TIMER1_OVF_vect) {tic++;}

ISR(TIMER3_vect) {
  if (TIFR3 & (1 << OCF3A)){
      TIFR3 = 1 << OCF3A;
      f_out = tic*0xFFFF + TCNT1;
      tic=0;TCNT1=0;
  }}  

#define DIN PD4
#define CLK PD2
#define CS  PD3
#define CAL 62502; //62499 = 1 sec 

static unsigned long tic,freq;
bool w=1;
byte fq[8],pd,x;

void setup(){
  PORTD |= (1 << PD5); // подтягивающий резистор на PD5 (вход T1)
  DDRB |= (1 << PB3); // D11 OUTPUT 8 MHz
  _delay_ms(2);
  DDRD |= (1 << DIN) | (1 << CS) | (1 << CLK);
  PORTD |= (1 << CS);
  WriteBit16(0x0F, 0);// тест выкл.
  WriteBit16(0x0C, 1);// вкл. индик.
  WriteBit16(0x0A, 0);// яркость
  WriteBit16(0x09, 0xFF);// дешифраторы вкл.
  WriteBit16(0x0B, 7);// кол-во разрядов
  cl();
  _delay_ms(2);
  noInterrupts();
// TIMER_1 INPUT T1
  TCCR1A = 0;TCCR1B = 0;TCNT1=0;
  TCCR1B = (1 << CS12) | (1 << CS11) | (1 << CS10);
  TIMSK1 = (1 << TOIE1);
  TCKCSR = (1 << F2XEN) | (1 << TC2XS1);
// TIMER_3 1 SEC
  TCCR3A = 0;
  TCCR3B = 0;
  TCNT3=0;
  TCCR3B = (1 << CS32) | (1 << WGM32);
  TIMSK3 = (1 << OCIE3A);
  OCR3A = CAL;
// TIMER_2 OUTPUT 8 MHz
TCCR2A = 0;TCCR2B = 0;TCNT2=0;
  TCCR2A = 1 << COM2A0 |1 << WGM21;
  TCCR2B = 1 << CS20;
  OCR2A = 0;
  interrupts();
}

void loop(){
 if(w==1){w=0;
  if(freq>=10000000){WriteBit16(0x0B, 7);x=8;}
  if(freq<10000000&&freq>=1000000){WriteBit16(0x0B, 6);x=7;}
  if(freq<1000000&&freq>=100000){WriteBit16(0x0B, 5);x=6;}
  if(freq<100000&&freq>=10000){WriteBit16(0x0B, 4);x=5;}
  if(freq<10000&&freq>=1000){WriteBit16(0x0B, 3);x=4;}
  if(freq<1000&&freq>=100){WriteBit16(0x0B, 2);x=3;}
  if(freq<100&&freq>=10){WriteBit16(0x0B, 1);x=2;}
  if(freq<10){WriteBit16(0x0B, 0);x=1;}

  fq[7]= freq/10000000%10;
  fq[6]= freq/1000000%10|0b10000000;
  fq[5]= freq/100000%10;
  fq[4]= freq/10000%10;
  fq[3]= freq/1000%10|0b10000000;
  fq[2]= freq/100%10;
  fq[1]= freq/10%10;
  fq[0]= freq%10%10;

  for(int i=0;i<8;i++){WriteBit16(i+1, fq[i]);}
  }
}

ISR(TIMER1_OVF_vect) {tic++;}

ISR(TIMER3_vect) {
  if (TIFR3 & (1 << OCF3A)){
      TIFR3 = 1 << OCF3A;
      freq = tic*0xFFFF + TCNT1;
      tic=0;TCNT1=0;
      w=1;
  }
}
void cl(){for(char i=1;i<=8;i++){WriteBit16(i, 0);}}
void WriteBit16(byte reg, byte data){  
     PORTD &= ~(1 << CLK);PORTD &= ~(1 << CS);
     for(int i = 7; i >= 0; i--){
        if(((reg >> i) & 1) == 1){PORTD |= (1 << DIN);}else{PORTD &= ~(1 << DIN);}
        PORTD |=(1 << CLK);PORTD &= ~(1 << CLK);
        }
     for(int i = 7; i >= 0; i--){
        if(((data >> i) & 1) == 1){PORTD |= (1 << DIN);}else{PORTD &= ~(1 << DIN);}
        PORTD |=(1 << CLK);PORTD &= ~(1 << CLK);
        }
     PORTD &= ~(1 << CLK);PORTD &= ~(1 << DIN);PORTD |=(1 << CS);
  }