Help! DIY 4 amp L297/6203 driver

[tribbles]

Wow thanks guys, thats a great help, now if i could just get someone to convert the schematic to a pcb and mill it for me.....

I can do the conversion of the schematic - I've done a fair number of PCBs myself (using Eagle PCB). Just send me the schematic, an idea as to what size you want (and also any heatsinks - most of the stuff I do is low-current digital, although the fan control was high current).

However, milling it... I photo-etch them myself, since I have the capability.

http://www.tribbeck.com/electronics/pcbs/

If you're interested

If you want to do it yourself, then there are a few rules to follow - graffian's advice is sound, but Eagle does have a "DRC" (Design Rule Check) which makes sure you don't break common ones (such as tracks too small, crossing over, pads too small, objects too close together). If you run this every so often as you're designing it, then it'll help you get along.

The photo-etching I do performs better than Eagle's built-in rules, so I've modified my rules to allow me to etch to within very tight tolerances.

Tribbles
Thanks for the very kind offer, Unfortunatly I have no idea where to start with the code. I can only guess that an output needs to modulate (or switch low) the vref line to set the hold current (possibly adjustable from a trim pot) and then an input needs to look for the clock pulse to reset full current when a signal is seen?

I would imagine that the timing's are going to be the hardest bit as it might loss the first step whilst switching back to full current?

Is there any reason why this couldnt be put on a separate board and just send the Vref lineto the driver board with the other signals?

Thanks again

I actually meant discuss with Irving

Looking at his (later) reply with the rough idea of the code, that looks sane to me, and roughly how I'd go about it.

INT0 would be the interrupt from the INT pin; INT1 would be the Timer0/1 interrupt.

DIP switches for the timeout's a neat idea - especially if it'll be used by someone who doesn't have reprogramming capability.

I have a slight concerna about using the PWM - if the PWM controls the direction control (i.e. oscillates between output 0 and open-collector), then that would be fine. However, from memory, it'll only oscillate between 0 and 1, then you'd need to be careful of the PWM pulse width - you could end up going too high with the VREF signal. Still doable though.

There's nothing stopping you from putting it on a separate board.