Dont know how to wire up paraller port with chip

[Devian]

Hey! I am trying to make same PC controlled stepper motor via com port.

I have different chip (SMA7029M) and i dont know how to wire up pins from com port to controller and so on.

Here i datasheet of my chip: http://www.allegromicro.com/en/Produ...7024/97024.pdf

Can you help me?

Best regards, Nejc

[amishx64]

That chip won't work for a CNC machine with a parallel port in the standard sense. The SMA7029M chip does not have any change direction pins, rather just MOSFET-type outputs for driving the motor in one direction. This chip basically acts like an intelligent H-bridge.

For instance, a more standard chip for CNC machines such as the TA8435H, has a pin [5] labeled CW / CCW Forward / Reverse switching terminal. That is not present on your SMA7029M chip.

What you could do is buy another chip such as the L297 that would act as an interface between your parallel port --> L297 --> SMA7029M. The L297 offers a direction change pin to make life easier and usable with standard CNC software. Downside is this adds price, a component and other little parts.

L297 data sheet that normally goes with the L298N. The L298N is what you would be replacing with your SMA7029M chip. See bottom of page 1.

If you really want, I could draw you up a schematic. Please decide whether or not you want to peruse this option before you have me put a few hours into a diagram.

Hope that helps.

[willie21a]

hey, got a unipolar motor from a printer i have the sma7029m chip from the same printer. what other chips can i use apart from the L297? ii have a sn74hc4020 which i got from the same circuit, would that be of any use? let me know cheers