Angular rotation of 90 degree

[cosmonavt]

I want to interface a stepper motor with an Atmega16 so that when executed, the motor shaft will rotate 90 degree and then stop. Suppose the step angle is 1.8 degree. We need 50 steps. How do I do this with a stepper?

 

[alec_t]

How do I do this with a stepper?

If you can find a suitable stepper-driver IC the datasheet should make clear which signals have to be provided by the micro.

 

[cosmonavt]

Actually I don't plan to use an IC, I want to know how to do this directly with the MCU.

 

[alec_t]

Check the threads listed at the foot of this page, or search this site. I'm sure this topic has been covered before.

 

[cosmonavt]

The threads on this site involve a driver IC. But I guess I should stay with Google on this one. Can't find very straightforward results but would be able to do some tweaks...thanks anyway.

 

[cosmonavt]

OK I think this is easy as anything. This Page explains this really well. One question though. This guy has used a PIC. I am using AVR. All Ports on the AVR Atmega 16 have internal pullup resistors. So would I need the hex buffer thingy?

 

[alec_t]

All Ports on the AVR Atmega 16 have internal pullup resistors.

Aren't those disabled when the pins are configured as outputs? Even if they aren't they may have too high a resistance to provide sufficient base current for the darlingtons used to drive the stepper coils; hence the hex buffer is advisable.

 

[Ian Rogers]

Nigel Goowdin's stepper driver seems to work ok

There are plenty examples on the net for driving them.