[lucas]

Have a look here how it all started:

http://www.cnczone.com/forums/showthread.php?t=22867

Attached is the PDF schematic for one axis.

Here is a picture of a 3 axis PCB using the TEA3718SP:
http://users.skynet.be/sky50985/CNC/..._tea/3axis.JPG

Fit's nicely on a eurocard (100x160mm) but needs a double sided PCB.
Single sided is possible but would need quite a few jumper wires.
These TEA3718SP's can be recuperated from printer PCB's or even bought new for a few buck's each, a lot cheaper than LMD's if 1 Amp (or a bit more) is enough for your application.

The concept of this R2R DAC can be used for other chips also.

Suggestions and feedback are welcome.

Regards,
Luc.

.

[Aiken]

Hi Lucas,

The pinout on your PDF does not match the Data sheet for TEA3718SP. Do you have an updated version of the schematic ?

Thanks

[lucas]

sorry for the mess, this one should be OK.

Can you please check it? Just to be sure.

Thanks,
Luc.

[hurricane13]

Nice job ! This is exactly what i was looking for. I know thisnis an old thread, but i found it while searching for microstepping info, and i happen to have a bunch of salvaged a3952sw's i want to use.

Im setting out to try building one based on your design now. ill be sure to post my results and diagrams. has any one else had any luck with other salvaged parts ?

thanks !

John

[mrendu43]

hello
can i use this tehnique to drive Vref of l297.
and parellel step and dir to pic and l297.

i dont know if comparators in l297 used for chopping are fast enough for this, and how much clock i will need for chopper. can i go as high as 20khz on

[lucas]

No, this only works if there are 2 Vref inputs, one for each phase.

[mrendu43]

true. bu i need only waveform for current controll.

phases will be ganerated by l297.

waveform for dacs ( reisstor network are the same ) only shifted by 90 degres

i read app note from ST and they stated that this can be done with l297 and l6208

[lucas]

It can be used with the L6208, this one has VrefA and VrefB input's.
The step (clock) input may not be used, The change in Vref voltages will cause the motor to step.
I don't see why a L297 is needed with the L6208.

[James Newton]

Love the PICStep, but I'm not all that impressed with the price on these drivers. I'm seeing $4-$5:
TEA3718SP Stock and Price by Distributor | FindChips.com