Controlling steppers

[raitl]

Ok, since I'm upgrading my robot project, adding a turret with a gripping hand and, I'm going to neet to control 3 more stepper motors, making total of 5 steppers. And since I'm using darlington arrays instead of dedicated stepper drivers, each stepper takes 4 I/O. My PIC16F876A is running out of I/O's... Hence the question... is there any way, side the dedicated controllers, to control a stepper with just 2 I/O lines?

And no, I'm not planning on replacing the steppers with servos either 8)

 

[theinfamousbob]

control a stepper with just 2 I/O lines?

It should be possible, depending on the type of stepper. If you're using steppers that can be driven by an H-bridge, just take two of the I/Os and invert them from the two overall inputs. A loss in resolution would occur, but depending on the application it might be alright. NOTE- this is just theoretical, I can't guarntee that it won't kill anything.

-Infamous

 

[bryan1]

Hiya Raitl,
The H-bridge chip from TI sn754410 is a widely used chip in robotics and can be controlled by 2 I/O's using an inverter chip. These chips can handle 1 amp per phase and can be stacked to double the amps. Give them a try and the datasheet shows how to hookup using 2 I/O.

Hope this helps

Cheers Bryan

 

[sureshd_eng]

I would like to introduce you revolutinary idea, that you can control all darlington arrays only using three pins of the pic microcontroler. Where you have to buy nother 2ICs numbered 74HC595.

for 74HC595 is serial to parallal converter IC that you can get 16 output pins as they connected and can send data to it using one pin of the PIC and other 2 pins are use for make data available to output and reset the chips.

If you need more data pls download the datasheet. or send me an email I will send you datasheets and some of my practical experiences.
sureshd_eng@yahoo.com

Suresh

 

[Nigel Goodwin]

I would like to introduce you revolutinary idea, that you can control all darlington arrays only using three pins of the pic microcontroler. Where you have to buy nother 2ICs numbered 74HC595.

Hardly 'revolutionary', it's been standard practice for decades.