/*******************************************************
This program was created by the
CodeWizardAVR V3.12 Advanced
Automatic Program Generator
© Copyright 1998-2014 Pavel Haiduc, HP InfoTech s.r.l.
http://www.hpinfotech.com

Project :
Version :
Date    : 19.10.2015
Author  :
Company :
Comments:


Chip type               : ATmega8A
Program type            : Application
AVR Core Clock frequency: 8,000000 MHz
Memory model            : Small
External RAM size       : 0
Data Stack size         : 256
*******************************************************/

#include <mega8.h>

// Declare your global variables here

// External Interrupt 1 service routine
interrupt [EXT_INT1] void ext_int1_isr(void)
{
USART_Transmit( unsigned char data )
}

// Standard Input/Output functions
#include <stdio.h>

void USART_Transmit( unsigned char data );
void USART_Init( unsigned int ubrr);

void main(void)
{
// Declare your local variables here

// Input/Output Ports initialization
// Port B initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRB=(0<<DDB7) | (0<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) | (0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization
// Function: Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRC=(0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) | (0<<DDC1) | (0<<DDC0);
// State: Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTC=(0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) | (0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=Out Bit3=In Bit2=In Bit1=In Bit0=In
DDRD=(0<<DDD7) | (0<<DDD6) | (0<<DDD5) | (1<<DDD4) | (0<<DDD3) | (0<<DDD2) | (0<<DDD1) | (0<<DDD0);
// State: Bit7=T Bit6=T Bit5=T Bit4=0 Bit3=T Bit2=T Bit1=T Bit0=T
PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) | (0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
TCCR0=(0<<CS02) | (0<<CS01) | (0<<CS00);
TCNT0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer1 Stopped
// Mode: Normal top=0xFFFF
// OC1A output: Disconnected
// OC1B output: Disconnected
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=(0<<COM1A1) | (0<<COM1A0) | (0<<COM1B1) | (0<<COM1B0) | (0<<WGM11) | (0<<WGM10);
TCCR1B=(0<<ICNC1) | (0<<ICES1) | (0<<WGM13) | (0<<WGM12) | (0<<CS12) | (0<<CS11) | (0<<CS10);
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer2 Stopped
// Mode: Normal top=0xFF
// OC2 output: Disconnected
ASSR=0<<AS2;
TCCR2=(0<<PWM2) | (0<<COM21) | (0<<COM20) | (0<<CTC2) | (0<<CS22) | (0<<CS21) | (0<<CS20);
TCNT2=0x00;
OCR2=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=(0<<OCIE2) | (0<<TOIE2) | (0<<TICIE1) | (0<<OCIE1A) | (0<<OCIE1B) | (0<<TOIE1) | (0<<TOIE0);

// External Interrupt(s) initialization
// INT0: Off
// INT1: On
// INT1 Mode: Any change
GICR|=(1<<INT1) | (0<<INT0);
MCUCR=(0<<ISC11) | (1<<ISC10) | (0<<ISC01) | (0<<ISC00);
GIFR=(1<<INTF1) | (0<<INTF0);

// USART initialization
// Communication Parameters: 8 Data, 1 Stop, No Parity
// USART Receiver: Off
// USART Transmitter: On
// USART Mode: Sync. Master UCPOL=0
// USART Baud Rate: 15625
UCSRA=(0<<RXC) | (0<<TXC) | (0<<UDRE) | (0<<FE) | (0<<DOR) | (0<<UPE) | (0<<U2X) | (0<<MPCM);
UCSRB=(0<<RXCIE) | (0<<TXCIE) | (0<<UDRIE) | (0<<RXEN) | (1<<TXEN) | (0<<UCSZ2) | (0<<RXB8) | (0<<TXB8);
UCSRC=(1<<URSEL) | (1<<UMSEL) | (0<<UPM1) | (0<<UPM0) | (0<<USBS) | (1<<UCSZ1) | (1<<UCSZ0) | (0<<UCPOL);
UBRRH=0x00;
UBRRL=0xFF;

// Analog Comparator initialization
// Analog Comparator: Off
// The Analog Comparator's positive input is
// connected to the AIN0 pin
// The Analog Comparator's negative input is
// connected to the AIN1 pin
ACSR=(1<<ACD) | (0<<ACBG) | (0<<ACO) | (0<<ACI) | (0<<ACIE) | (0<<ACIC) | (0<<ACIS1) | (0<<ACIS0);
SFIOR=(0<<ACME);

// ADC initialization
// ADC disabled
ADCSRA=(0<<ADEN) | (0<<ADSC) | (0<<ADFR) | (0<<ADIF) | (0<<ADIE) | (0<<ADPS2) | (0<<ADPS1) | (0<<ADPS0);

// SPI initialization
// SPI disabled
SPCR=(0<<SPIE) | (0<<SPE) | (0<<DORD) | (0<<MSTR) | (0<<CPOL) | (0<<CPHA) | (0<<SPR1) | (0<<SPR0);

// TWI initialization
// TWI disabled
TWCR=(0<<TWEA) | (0<<TWSTA) | (0<<TWSTO) | (0<<TWEN) | (0<<TWIE);

// Global enable interrupts
#asm("sei")

while (1)
      {
      // Place your code here

      }
}

// PIC12F629 Configuration Bit Settings

// 'C' source line config statements

#include <xc.h>
#include <stdint.h>

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

// CONFIG
#pragma config FOSC = INTRCIO   // Oscillator Selection bits (INTOSC oscillator: I/O function on GP4/OSC2/CLKOUT pin, I/O function on GP5/OSC1/CLKIN)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT enabled)
#pragma config PWRTE = OFF      // Power-Up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = OFF       // GP3/MCLR pin function select (GP3/MCLR pin function is MCLR)
#pragma config BOREN = ON       // Brown-out Detect Enable bit (BOD enabled)
#pragma config CP = OFF         // Code Protection bit (Program Memory code protection is disabled)
#pragma config CPD = OFF        // Data Code Protection bit (Data memory code protection is disabled)
//========
#define _XTAL_FREQ  4000000L

//========
#define MOSI      GP0
#define MISO      GP1
#define SCK       GP2
#define SS        GP5

#define GPIO_Tx   GP4
#define TRIS_Tx   TRISIObits.TRISIO4

//========
//
//========
const uint8_t arr_data[] = {
    0x00
};

unsigned char flag;

enum {
    reset = 0,
    in = 1,   //приняли байт
};
//========
//
//========
void Init_MCU(void);
void SPI_write_LSB (uint8_t);
void SPI_send_arr_data(void);
//========
//
//========
void Init_MCU(void) {

    GPIO = 0;
    CMCON = 7;
    TRISIO = 0b00010010; //GP4,GP1 input

    GPIF = 0;
    GPIE = 1;
    IOCB4 = 1;  //GP4 interrupt
    PEIE = 1;
    GIE = 1;
}
//========

void main(void) {
    Init_MCU();
    SS=1;
   
    while (1) {
        switch(flag) {
            case in: SPI_send_arr_data();
            break;
        }
        __delay_ms(100);
    }
}
//========
//
//========

void SPI_send_arr_data(void) {
    SS = 0;
    for (uint8_t i = 0; i<sizeof (arr_data); i++) {
        SPI_write_LSB(arr_data[i]);
    }
    SS = 1;
    flag = reset;
}
//========
//
//========
void SPI_write_LSB (uint8_t data) {
    unsigned char mask = 0x01;
    while (mask) {
        if (data & mask)MOSI = 1;
        else MOSI = 0;
        SCK = 1;
        __delay_us(46);
        SCK = 0; //
        __delay_us(46);
        mask <<= 1;
    }
}
//========
//
//========

interrupt void IRQ(void) {
    flag = GPIO;
    if (GPIF && GP4 == 0) {
        flag = in;
    }
    GPIF = 0;
}
//========
//
//========

...
OSCCAL = _READ_OSCCAL_DATA();
...