I am using a ATMEL 8515 to control the steps of a 1,2A 6V motor. I tried to create a drive and it works well in low speed, but if I use a higher speed I have problems. The TIP120 becames very Hot and it seems like the motor has lost the steps and it stay immovable and just start to tremble. Do you know how can i solve this problem ??? Thank you Again, anyway.