Graynomad, thank you so much for a quick reply but you have not fully understood my problem. Higher baud rate (115200) is not my problem..Lower baud rate is my problem, motor slows down at lower baud rate and I don't want that.
I have not modified the standard library apart from Serial.println(_currentPos); . Don't dout i have embedded code and hidden you.
Can you suggest me how can I modify my program to not slow down the motor at any baud rate?
Where should I write serial.print() function?