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Ground pins connection in L293D with PIC16F628

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khansaab21

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Hello guys. I have to use L293D (motor driver) with PIC16F628. Have got only 1 question

Q) Does the digital (5V) and analog (12V) grounds have to be common and all the four ground pins have to be connected to it. Or two ground pins are for digital supply while the other two are for analog supply and digital and analog grounds have to be kept separate.
 

Re: L293D with PIC

khansaab21 said:
Q) Does the digital (5V) and analog (12V) grounds have to be common and all the four ground pins have to be connected to it. Or two ground pins are for digital supply while the other two are for analog supply and digital and analog grounds have to be kept separate.
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All the ground pins should be conneted together to complete the cicruit. Not connecting the grounds will isolate the two supplies and the controls given from the PIC will not be executed by the L293 section without ground refernce from the later and vice versa. Cheers
 

L293D with PIC

Ok friend. I got it so far i.e. all four ground pins of L293 have to be connected together. Does that mean digital and analog grounds have to be common ??

And if digital and analog grounds are tied to each other, then wont it effect the circuit operation?? As this circuit employs serial + blue tooth communication simultaneously and timing has to just perfect.
 

L293D with PIC

No...It shudnt affect. As per you have described the circuit, it shud only work if the grounds are tied together. Cheers
 

Re: L293D with PIC

The L293(D) does not have seperate grounds for logical and driver supply. They are already connected together internally. But still you have to connect the 4 ground pins together externally, preferably with a large ground plane for power issues.

Take care that the logical power supply is well stabilized and decoupled with some 100nF capacitors. If your logical power supply is derived from the driver power supply, and if you have problems with spikes from inductive loads on the L293D, try adding some small capacitors in parallel with the load. If there are still problems, insert an L-C filter between the driver power supply and the logical power supply regulator.
 

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