How to enable EPP on PCI parallel port card

Like John said, I doubt that the mode of the parallel port makes any difference at all with EMC, at least EMC is not going to use the port in EPP mode.

You just need to get the right charge pump signal (10 KHz?) on the right pin (16) and you should be good
This does require a 20 KHz+base thread

From the manual...

CHARGE PUMP: The G540 is equipped with a charge pump (watchdog timer) that disables the drive without a 10 kHz signal on pin 16 of the DB25 port. You can enable this by reversing what was done in
STEP 3 and making sure that your parallel port is set to EPP mode. To do this, go into BIOS and set your parallel port to either “EPP” or “Send/Receive”; most parallel cards are set to ECP or “Send Only” by default.

Perhaps not true?

Maybe not true with emc?

But it does give the impression you need EPP for the charge pump.

You of course could run without a charge pump but it is a good safety feature if you can use it.

A cable that works with a printer may not in fact have all the connections you need for emc, but you can test it with a meter and or the parallel port tester.

Rick G

That manual sounds a little confused.

IEEE 1284 parallel port modes are:

SPP (old unidirectional)
Bi-Directional (PS2)
EPP
ECP

Seems _very_ unlikely that EPP is needed for the charge pump especially since the charge pump is connected to a signal (pin 16 = /INIT) that the EPP state machine has no control over, and in fact
the state of the /INIT pin is just a set by a control register bit in SPP, Bidirectional, and EPP mode

Have you checked to see that the charge pump signal is there? Your troubles may be that the G540 needs too much source drive (parallel ports sink current better than source) on its charge pump signal
for the port to actually source (especially a 3.3V PCI card)

Apparently these newer EPP capable cards rely on some kind of handshaking in software to change modes.

So one of the ways for EPP to be enabled in Mach 3 or even EMC2 will be if the software requests it to switch modes? Maybe one can write a script to switch mode?

I do know that on my motherboard parport where I can turn EPP on, I can get chargepump to work.

On my PCI parport, it doesnt work even though settings are the same, only the address is mapped to the PCI card, which is in ECP mode.

I beleive some cards can be set to EPP mode if needed with software. Which card do you have and what chip?
You might want to look at the info on EPP here...

wiki.linuxcnc.org/emcinfo.pl?PPMC_Board_Set

and elsewhere on the EmcKnowledgeBase

Rick G

One possibility is that the parallel port current drive capability is higher in EPP mode

We have had a customer using a G540 with our FPGA cards and they required a 5V buffer to drive the charge pump signal. The FPGA outputs are 3.3V with 24 mA source and sink capability (much more than a 3.3V parallel port)

So if your PCI parallel port is a 3.3V one it may simply not work whatever you do.

I consider the fact that the G540 needs a high source current >3.3V signal on its charge pump input a design flaw