Pictures of CNCDuDeZ New USB-Parallel Interface.

[CLaNZeR]

Just assembled the first protoype of the USB-Parallel Interface and it works a dream.

This will let you send Gcode via USB to any Motor control box that usually gets it's data via the Parallel Port.

There has been alot of debate over whether this will work because of the latency of the USB Port and alot of talk has gone on about having fancy DSP chips and lots of memory.
This design has not required that and is built round a cheap Processor which costs less than £5.00 and works just fine.

We are releasing the build details of the Interface below Free to charge, so anyone can make it and develop for it.



Simply plug one end of the circuit into your USB Port and XP will auto detect it as a HID Device, so no extra drivers needed.
Then plug your 25way Parallel lead into the other that goes to your controller box and you are ready to go.

With the is release we will be supplying the following all FREE of charge.

PCB Layouts in JPG format and Gcode format for people wanting to mill their own PCB.

Full Component list and placement.

Beta USB Gcode Test Application (supports G00 and G01 to begin with).

Firmware for the Processor.

Full Protocol and command set for people wanting to develop their own software.


To cover all the different pin configurations out there, we will also offer a free service to compile the firmware to suit your controller and release it on the site.
We have full control of all 17 pins that can be used on the Parallel Port and can cover all configurations where needed.
The first firmware released will be for the following pin configuration as used on the Xylotex Board and a few others.
Pin2: Step X-Axis
Pin3: Direction X-Axis
Pin4: Step Y-Axis
Pin5: Direction Y-Axis
Pin6: Step Z-Axis
Pin7: Direction Z-Axis
Pin10: Z-Limit Switch
Pin11: Emergency-Stop Switch
Pin12: Y-Limit Switch
Pin13: X-Limit Switch

I will try and upload all the details tomorrow night.

Regards

Sean.

[pminmo]

Sweet,
How do you plan on keeping the WinXP tasks not related to CNC from interferring with the USB data stream?

[kdoney]

CeWin will allow you to run Windows CE (a hard real time system) concurrently with XP so you can have a deterministic usb connection and share the data, through IPC, coming from Mach 3. VenturCom ETS (formerly know as Phar Lap ETS) has an XP extension called RTX that is a hard real time extension to XP which will allow you have IPC with Mach 3 and still connect to the usb port deterministically. VenturCom is a little more expensive.

[CLaNZeR]

Well at the moment testing it, I have had no problems with any glitches at all and have gone off checking email without the stream really being interupted.
I am sure if I was opening different applications then this would effect it, but this is the same with using the printer port anyway, but not so severe.

Also remember say we wanted to move from 0,0 to 0,200 then this is one usb packet of 11 bytes as the processor does all the counting, pulse creation and monitors for the limit switches and emergency stop.
If we go say 0,0 to 10,200 then again one command because the code in the processor will work out the correct travel for each axis to give you the correct cut line.

If you were sending out the same output for 200mm travel in microstep mode your printer port would have to pulse out 106666 pulses and even just moving the mouse in XP can cause that to judder.

It is when you are say cutting out a circle the packets will increase with the all the little movements being sent. I want to add the G02 that will cut out that a bit as well in the future.

And to top it all future plan is too use the extra leftover pins of the processor too either connect some extra memory. I have been playing with a new host processor IC that talks sweetly to the Pic Processor over 4 control lines and can read SD cards as well as USB Memory sticks, so maybe this is another option in the future.

Also the extra pins left could be used to add the manual Jog.


Regards

Sean.

Originally Posted by pminmo Sweet, How do you plan on keeping the WinXP tasks not related to CNC from interferring with the USB data stream?

[PEU]

waaay cool, I cant wait to see it working with other gcodes. I have the pic (18F4550 right?) and the others parts ready to build in my parts box

can encoder inputs be added so you can check discrepancies between the movement order and the actual movement?

mpg is also good to have.

Im keeping close eye on this!!! thanks


Pablo

[CLaNZeR]

Components are:

1 * 25pin socket
1 * 18F4550 Chip
1 * USB Socket
1 * 20mhz Xtal (the pic internally clocks this upto 48mhz)
2 * 22pf ceramics
1 * 4k7 resistor
1 * 1k resistor
1 * LED
1 * 0.1uf ceramic decoupling cap.
1 * 0.1uf electrolytic capacitor
1 * 22uf electrolytic capacitor
1 * little tactile push switch for resetting Pic, not really needed.

And a PCB about 75mm * 75MM

You will need a Pic Programmer that supports the 18F4550 but these can be bought or made very cheaply.

Because we are using the 40 Pin Processor there are plenty of pins left for adding on encoders to monitor and correct the turns on the motor.

So if you want any test routines popped in the formware, then let me know what encoders you are using and the pulse to revolutions and will try and add.


Regards

Sean.

Originally Posted by peu waaay cool, I cant wait to see it working with other gcodes. I have the pic (18F4550 right?) and the others parts ready to build in my parts box can encoder inputs be added so you can check discrepancies between the movement order and the actual movement? mpg is also good to have. Im keeping close eye on this!!! thanks Pablo

[rippersoft]

Wow man! Your contribution is really great. This pretty much puts to rest the exercise of USB conversion. I went to your sight and had a look. Impresive little machines you build. I really like the xmas CD idea. I will have to pop some of those out this year.

Thanks for your hard work.

[CLaNZeR]

Thanks Ripper for the feedback and you are more than welcome.

This is just a Hobby to me in my spare time, but hey it's fun and hopefully helps others out that wanna play!


Regards

Sean.

Originally Posted by rippersoft Wow man! Your contribution is really great. This pretty much puts to rest the exercise of USB conversion. I went to your sight and had a look. Impresive little machines you build. I really like the xmas CD idea. I will have to pop some of those out this year. Thanks for your hard work.

[CLaNZeR]

Forgot to say:

I have just uploaded all the things you wil need to now build and test out the new Interface.

Please leave feedback here on any good or bad points and also any features you would like to be added.

We had great feedback on email from the previous release "remote jog" project, but placing it in these forums will hopefully help other people who want to build and play with different enhancements to their machines.

Regards

Sean.

[pminmo]

Sean,
Excellent, congrats on your accomplishment. A start at getting away from the PPort is long overdue.

[H500]

Looks like an interesting project! But just to clarify... the circuit is not useable with the commonly available CNC programs like Mach3.

[CNCRob]

I was just looking at your website. It looks like you have a pretty nice line of products.