Ed, You can always disable the holding current by using ENABLE1 and ENABLE2 on the L293D (pin 1 and pin 9 on the DIP version). Pulling one of these pins LOW will disable the coil current. Maybe these 2 pins can be your friends if you cannot get up to speed using SPI. This seems very much the case, as I had made a wrong calculation of 96RPM maximum by assuming 144 steps per revolution, instead of 400! Edwin --- In basicx@y..., "edstewbob" <edstewbob@y...> wrote: > Edwin, > > Thank you very much for your answer. I will look into using SPI. > For my application I am able to get about 120 RPM from a 400 step > per rotation motor at full step increments using 4 output ports > directly with the l293D. I also used the E-labs E1204 controller > with 3 BX-24 pins: PWM, forward/reverse, full/half step. My > application requires driving the motors with battery power so I wish > to optimize power consumption. With a more direct control of the > motor stator coils I can turn the coil power off when not required > and the holding torque of the motor maintains position. With an > external controller it seems to always maintain power to the coils > and the batteries drain down more quickly. If I can use SPI to > interface with the L293D then this will be a good solution. |