USB controlled steppers

[Gaurav]

I'm doing a proj where i have to build a controller to control 3
steppers which will move along xyz. This controller has to have USB
interface.
My scheme is to use a dedicated motion controller IC like TMC428 from
Trinamic ; the IC has a serial interface. And use a USB translator to
give it the serial data.
PC -> USB translator -> TMC 428 -> drivers -> motors
I've tried looking for microcontrollers with USB interfaces but they
bring too much redundancy.
Ne suggestions ?

 

[Ken Smith]

[... USB ...]

Some months ago Nuts and Volts had an article on a USB interface that had
some number of digital lines out of it. I suggest you look up the
article. It could give you a very simple USB interface.

 

[Roger Hamlett]

I'm doing a proj where i have to build a controller to control 3
steppers which will move along xyz. This controller has to have USB
interface.
My scheme is to use a dedicated motion controller IC like TMC428 from
Trinamic ; the IC has a serial interface. And use a USB translator to
give it the serial data.
PC -> USB translator -> TMC 428 -> drivers -> motors
I've tried looking for microcontrollers with USB interfaces but they
bring too much redundancy.
Ne suggestions ?

It is down to how many you want?.
The cheapest solution, is to ue an 'off the shelf' USB-serial converter.
These are built into cables, and are about as small as possible, and are
priced for less than you can get the chips themselves.
The second solution, is to use a 'module', or the chips from these (such
as the FTDI units). Work well, and drivers for the RS232 'virtual'
interface are allready present.
The third solution, is to use the USB interfaced micro, and get rid of the
motion control chip. Basically, and acceleration/deceleration profile, is
pretty simple to implement in most micro controllers, and you can then
drive the motors with just a power interface IC. You can even use a PWM
output, combined with an ADC input to implement the current control for
the stepper.
If you are building a reasonable number of units, the latter is the 'best'
solution. Otherwise just use an off the shelf converter. A chip like the
FT232BM, makes it pretty simple, if you want to put the converter 'on
board'.

Best Wishes

 

[Steve Parus]

http://www.phidgets.com

is working on a USB stepper controller/driver.

See their Kits for USB digital IO.