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???
01/26/05 12:50
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 		 #85795 - Get your thinking hat on
Responding to: ???'s previous message
Wong Chi Fai said:
i have to interface the MCU directly to the motor without the driver. Hence, i tried to use 4 pins from Port 1 (P1.0 to P1.3) to connect to the 4 pins of the motor, and tried writing code for generating the signal for the motor, but result was that the motor didn't move at all.
Does anybody what is wrong with that?

Think about it:
  • How much current can a port pin sink?
  • How much current can a port pin source?
  • How much current does your motor need?

    And i have searched some example on the Internet, but all of them use a driver to drive the motor.

    Don't you think there might be a reason for that...?

    And from this forum, i found a old post and someone said that "you must upgrade your current with transistors...

    See above.

    ... and use diodes to defend back emf "
    Is it really needed??

    Again, think about it: what happens when you suddenly turn off the current through a coil...?


    • List of 42 messages in thread
    TopicAuthorDate
    Question about Step motor, thanks            01/01/70 00:00      
       Get your thinking hat on            01/01/70 00:00      
          Detail            01/01/70 00:00      
             Are we nearly there yet?            01/01/70 00:00      
                look here also            01/01/70 00:00      
                   checked..            01/01/70 00:00      
                      You got it.            01/01/70 00:00      
                         I have got it.            01/01/70 00:00      
                            I have studied some example..            01/01/70 00:00      
                               Why?            01/01/70 00:00      
                                  Because...my supervisor            01/01/70 00:00      
                                     How about this design?            01/01/70 00:00      
                                        Maybe this also will help            01/01/70 00:00      
                                           This website is really useful            01/01/70 00:00      
                                        I doubt if it will fly            01/01/70 00:00      
                                           Thanks            01/01/70 00:00      
                                              do not forget            01/01/70 00:00      
                                                 If i use an IC now            01/01/70 00:00      
                                                    Saa 1027            01/01/70 00:00      
                                                       ULN2003?            01/01/70 00:00      
                                                          it must be your teacher            01/01/70 00:00      
                                                             No, is my supervisor            01/01/70 00:00      
                                                                unipolar/bipolar.            01/01/70 00:00      
                                                                   4            01/01/70 00:00      
                                                                      stepper motors            01/01/70 00:00      
                                                                         not clear            01/01/70 00:00      
                                                                            4 lead motor            01/01/70 00:00      
                                                                               but            01/01/70 00:00      
                                                                                  8 lead steppers            01/01/70 00:00      
                                                                                     DC drives            01/01/70 00:00      
                                                                                  Unipolar / Bipolar            01/01/70 00:00      
       This might help            01/01/70 00:00      
       I had the same problem            01/01/70 00:00      
          Toasters            01/01/70 00:00      
             Toasters            01/01/70 00:00      
       PWM to drive the stepper motor            01/01/70 00:00      
          that is wrong            01/01/70 00:00      
             PWM Steppers ?            01/01/70 00:00      
                it's tough to google on 297            01/01/70 00:00      
                   Brought to you by the letter L            01/01/70 00:00      
                      Try to check out this site            01/01/70 00:00      
       It is Impossible            01/01/70 00:00      

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