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Topic: Motor Driver Chip SN754410 doesn't work (Read 655 times) previous topic - next topic

Zhao

Hello!

    So I am trying to use Arduino to control my motor.

   I connect the pin 12, pin 13 on my arduino to the 1A and 1,2EN on SN754410 (Here is datasheet http://www.sparkfun.com/datasheets/IC/SN754410.pdf ).

   I didn't connect 2A,2Y,3A,3Y,4A,4Y,3,4EN,VCC2,GND3,GND4

   After setting 1A and 1,2EN to be high, what I can observe is:

   VCC1: 12V    1A, 1,2EN : 3 ~ 6V (Keep changing,Never lower than that value)   1Y (output volate to motor): 0.66 V, should be same as Vcc! Wrong
   GND1,2 = 0, All other pins have a little voltage like 1V or 2V....

    Why the output voltage is so low.... what should I do? Should I just connect all pins? Or should I add some kinds of capacitor / resistor circuit?

Thanks!

dc42

#1
Jan 21, 2012, 11:46 am Last Edit: Jan 21, 2012, 11:49 am by dc42 Reason: 1
You should connect Vcc1 to Arduino +5v (logic supply) instead of +12v, and you need to connect Vcc2 to +12v (motor supply). Also it's best to connect all the grounds, and to connect at least the unused EN inputs to ground.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Zhao

thanks...
the reason we use 12V for VCC is because the motor requires a 12-36V to work functionally....
any other way to fix it? like a capacitor or resistor?
there is already a capacitor at motor...

dc42

You only need to feed 12v (or whatever the motor needs) to Vcc2. Vcc1 powers the logic, not the motor.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Grumpy_Mike

As you have put more voltage into the logic power pin than it was designed to take you might have damaged the chip or your arduino.

dc42

I don't think so, according to the datasheet http://www.ti.com/lit/ds/symlink/sn754410.pdf Vcc1 is (unusually) rated at 36v. Although the recommended range is 4.5 to 5.5v.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

ajofscott

If he had read the whole document, it shows how to connect the ic.

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