I am trying to drive a 6v dc motor with L293D driver and Atmega8 without PWM. The problem is i am getting very low speed while connecting the motor with L293D driver. But, it rotates well when i provide direct 6V dc supply to the motor. I am using external 6v source at VS(motor supply) pin of L293D, but no improvement. The motor does not rotate until i turn the rotor with hand. What could be the problem? My code is here:

    DDRB = 0xFF;
    while(1)
    {

    PORTB = 0B00000010;
    _delay_ms(20000);

    }

My simulation design is here:
![Interfacing DC gear motor with Atmega8][1]


  [1]: https://i.sstatic.net/rY3DL.png