Mesa 5I25 + 7I77

tommylight wrote: If you plan on using a simple Torch Height Controller like the Proma elektronika THC150 or some other types that output UP/DOWN/ARCOK signals, for the time being you will also need that parallel port besides 5i25/7i77, to drive a stepper motor for the Z axis.

It is possible to drive a stepper (slowly) using the 7i77 GPIO, or to connect a stepper breakout card to the spare connector on the 5i25.

andypugh wrote:
It is possible to drive a stepper (slowly) using the 7i77 GPIO, or to connect a stepper breakout card to the spare connector on the 5i25.

That is my next point of attack, as it needs some editing of the thc.hal file, some of the pins for parallel port stepper and mesa stepper are not the same, and i have not yet had time to figure it out.

Is it possible to mate the 7i77 with any other PCI-Parport card. For example, the "StarTech PCI1P_LP "

Or there are hundreds of PCI-Parport cards available in India. Can I use any of them. Or is there anything specific in the 5i25, that is missing in the other cards.

Please let me know the possibilities

I do not think you can, but PCW knows much better than me, so he might chime in.

No it can't. The DB-25 port Mesa cards like a 5i25, are FPGA cards not parallel port cards. They read and process the data communicated through the port unlike a parallel port wich is simply digital I/O.

CNCSREEDHAR2016 wrote: Is it possible to mate the 7i77 with any other PCI-Parport card. For example, the "StarTech PCI1P_LP "

Yes, but it wouldn't work

You probably could use a 7i76 with a generic parallel port as a step/dir breakout. But not the 7i77. If you look at the pin allocation:
github.com/LinuxCNC/hostmot2-firmware/bl...PIN_7I77_72.vhd#L110
The pins on the DB25 are a combination of 2.5Mb serial data and multiplexed encoders. The serial handles the GPIO and analogue outputs, the multplexed encoders read 2 sets of ABZ encoder data on only three pins.

The 5i25 is not _that_ much more expensive than a parallel port card, and has the advantage that it can do PWM, encoder counting and step generation at 10MHz, whereas a parallel port can do all those at 20kHz.