hpwm motor driver datasheet

[ArnieW]

I've been looking at the 14M specs and interested in the hpwm command. There is a reference in the manual to a motor driver datasheet but it doesn't seem to be listed on the website.

Am I looking in the wrong places or is this still being written?

thanks, Arnie

 

[Mycroft2152]

The hpwm command is pretty clever.

Unfortunately, you have to give up a couple of inputs to use it.

On the other hand for the price of the 14M ($4US) it will be a great self contained motor driver that ccan be easily added to any project.

 

[Technical]

Still writing it! If you are technically minded you can also lookup 'enhanced pwm module' in the Microchip PIC16F684 datasheet.

 

[ArnieW]

OK, thanks for the update technical. I guess for the time being I'd just like to know if I can use a 14M with hpwm to drive an L293D to then drive a motor?

What I am specifically after is a reversible motor driver with variable speed. I want to build a psuedo servo motor controller - one that will direct a motor to a particular spot, slow down when close, and turn off when in position.

I'm not quite sure if the half bridge configuration will do this.

thanks for your help, Arnie

 

[hippy]

I can't answer your questions, but Microchip Application Note AN893 may be of interest to you - <A href='http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&amp;nodeId=1824&amp;appnote=en012134' Target=_Blank>External Web Link</a>

 

[ArnieW]

Thanks Hippy, I'll check it out.

 

[ArnieW]

I think I now understand what is going on with full bridge control of a bidirectional motor and the PIC16F684 architecture. I was hoping to use 2 control lines to control the motor, but because pwm is being used, it looks like I will need four: two to provide the logic 1 or 0 and two to provide the control (pwm) signals. If I am reading this right, the only way to use a full bridge with two control lines is if the 'ON' control line also provides the logic 1 the bridge needs, while the 'OFF' control line providing the logic 0 the bridge needs.

I hope that makes sense - can someone who knows more about these things confirm or otherwise my muddled logic?

And a follow up question - what is a half bridge configuration useful for?

thanks, Arnie

 

[hippy]

An alternative is to use external inverters to create the additional two signals for the full bridge driven in half bridge configuration, or use half bridge to control a +V to motor and a -V to motor switch ( common mid-point join ) with the motor then to 0V.

These modes are, somewhat briefly, described in the 16F684 datasheet in section 11.4