Help! DIY 4 amp L297/6203 driver

[irving2008]

Thanks for the replies...
Irving

So is the Pic just earthing the 5v supply to the VREF making it 0v which means there is no holding current? I presume it would then revert back when a pulse is detected on the clock line?

Well if that was the case it would be pointless IMHO. I had a quick scan round and can't find the original design writeup for this circuit. I am wondering if the PIC modulates the VREF rather than just shutting it off...

[tribbles]

Well if that was the case it would be pointless IMHO. I had a quick scan round and can't find the original design writeup for this circuit. I am wondering if the PIC modulates the VREF rather than just shutting it off...

It could do that - it would reduce the holding torque for the motors as a result. It would then provide the "full" VREF when it's being clocked. It might be a very short pulse...

[Ross77]

Modulating the vref would make sense as no holding current isnt much use. Is that why a Pic is used rather than a 555?

I did find another cuircuit that uses logic gates to trigger 2 separates trim pots but the control signal came from an external source or the software. would it be possible to use a 555 chip to trigger this circuit?


This would make more sense and be easier to setup