make a 38 KHz IR-remote control frequency with delay function

Question

I try to make a 38 KHz carrier IR remote control frequency using delay function. When I press the key named "tasto1" the remote could send from ir led the carrier but I don't see nothing on the ocilloscope.The remote control have a ATtiny 2313V mcu and I wrote the code in avr-c using avr-gcc compiler. Is there something wrong with this code?:

    #include <avr/io.h>
    #define F_CPU 4000000UL
    #include <util/delay.h>
    #include <avr/pgmspace.h>
    #include <avr/interrupt.h>
    #include <avr/sleep.h>
    #include <util/atomic.h> 
    volatile uint8_t tasto1= !(PINB6 & PIND2);
      int main()       
          {
           DDRD = 0x01; 
           PORTD = 0x00; // LED on PD0 output low (sink) for hardware modulator
              while (1) {
                         if (tasto1==0){                  //enable IR driver
                          PORTD &= ~(1 << PD0);
                          _delay_us(18);
                          PORTD |= (1 << PD0);
                          _delay_us(8);
                          }
                          else { DDRD=0x00;}
                        }
                     } 

When I compile and upload the hex code on the mcu I haven't errors. I must use the delay function solution because the dedicated pins to make timers are mapped (wired) to be used like keys.