Pluto servo parallel port protocol

Could anyone explain me how EMC is communicating with Pluto servo over the parallel port, because I will design a new circuit but with AVR microcontroller

I've been studying several different parallel port configurations, so I am a bit confused, but I think this is how it works. The link between EMC2 and the Pluto is through EPP, which has an Address register and a Data register on the parallel port card. Somewhere in the Pluto documentation is a list of Pluto registers and addresses. First you place a Pluto address in the parallel port EPP Address register, then the parallel port takes over and sends it out to the Pluto. Then you load the parallel port Data register with the data you want to sent to the the Pluto address, then the parallel port sends it. I believe successive data automatically loads to successive Pluto addresses, so you don't need to send an address for each register. I believe the Pluto driver starts by setting the address to 0 then fills the full address space on each servo period. Reading Pluto registers is done in a similar way -- write an address, then read successive data bytes.

Since EPP is broken for most popular parallel port cards, I abandoned EPP for my AVR project and I'm working on using bi-directional SPP. This is much slower, but may be much more flexible. I don't really know if it will work, but we'll see.
--
Kirk Wallace
www.wallacecompany.com/machine_shop/
www.wallacecompany.com/E45/index.html
California, USA

Thanks, I found the pluto register layout file with some explanation about communication between them.
Now I must make some experiment with my new board to see if this will work. I know it will be much slower than an FPGA. 40 MHz of 4 channel encoder count is not possible with microcontroller but I will be satisfied with 200 kHz rate

Do you have a page that describes your project, what AVR you're using, what your goals are, etcetera. I started an AVR wiki page here: wiki.linuxcnc.org/emcinfo.pl?AVR . Feel free to add to it. I need to move the more generic information, such as BLDC drivers to another page and make it more AVR centric.

I am currently playing with an ATmega32, but plan on moving to an ATXmega to get more speed, more PWM channels, and other goodies. One problem is the Xmega's are 3V only, so there are some interface issues.
--
Kirk Wallace
www.wallacecompany.com/machine_shop/
www.wallacecompany.com/E45/index.html
California, USA

For now I abandoned my AVR-pluto project because I got one CYCLONE FPGA. With this device I build a PCB with buffer I/O 74HC245(because device not 5V tolerant).The test program ledblink from KNJN site worked well. So now I have another problem and don't know where to search for resolve it.
How the pins from parallel port are connected with the APEX FPGA on pluto board ?
I found some documentation from one russian forum but didn'twork with my board.
I think some signal are missing, or maybe there are connected through some transistor to invert signal.

If someone can help ?

Later I will publish everything if the board will work for me !!!

Thanks folks

forum.rcdesign.ru/f110/thread185343-2.html
forum.rcdesign.ru/attachment....3&d=1285250625
forum.rcdesign.ru/attachment....4&d=1285250632

I can help you with CYCLONE FPGA
My Fpga board is forum.rcdesign.ru/f110/thread185343-2.html