dc motor not working

[peterdon]

hello friends...
i am very new to mc9sdp512..
my problem is that , i attached a dc motor directally to port B

+ve wire on PORTB_PB0

-ve wire on ground ...............

in the program i have set the PORTB_PB0=1;
and debug it in TBDML mode
and i got output on PORTB_PB0=4.49 volts..i have checked it with multimeter...!!

but my motor is not moving.....!! even i hv tested my motor on 3 volts battery then it is running........................

any suggestion please..........!!

[Gunde]

Hi.

Normally a port pin can just source some few mA, it´s intended to drive logic circuits.

If you want to drive something more demanding you should use a driver circuit with at least a transistor.

I normally use some ULN-driver, FET or a standard bipolar transistor.

If you connect an inductive load without protection you can easily damage the controller because of the overvoltage induced then you cut the power to the inductance, so please take care.

Br. Gunde

[peterdon]

hey thank u so much...for the reply...
but i have another problem now ...........

i want to drive a stepper motor 32kgcm requires 2.5 amps of current....

what driver circuit should i use ??
and how to make my own driver circuit for heavy stepper motor..???