How to enable EPP on PCI parallel port card
17 Nov 2011 08:04 #14888
by Rick G
Replied by Rick G on topic Re:How to enable EPP on PCI parallel port card
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
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
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17 Nov 2011 14:46 - 17 Nov 2011 14:46 #14900
by PCW
Replied by PCW on topic Re:How to enable EPP on PCI parallel port card
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
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
Last edit: 17 Nov 2011 14:46 by PCW.
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17 Nov 2011 15:00 #14901
by andypugh
Replied by andypugh on topic Re:How to enable EPP on PCI parallel port card
PCW wrote:
In that case, would a pull-up (from the USB 5V, maybe) be a solution?So if your PCI parallel port is a 3.3V one it may simply not work whatever you do
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17 Nov 2011 15:28 #14902
by PCW
Replied by PCW on topic Re:How to enable EPP on PCI parallel port card
Possibly
It has been speculated before that on some parallel port chipsets setting different modes
changes some I/O pins from open drain with pullups to push pull. If this is what is happening on
/INIT = G540 chargepump, then yes a stiffer pullup (say 470 Ohms or so) may fix the problem
It has been speculated before that on some parallel port chipsets setting different modes
changes some I/O pins from open drain with pullups to push pull. If this is what is happening on
/INIT = G540 chargepump, then yes a stiffer pullup (say 470 Ohms or so) may fix the problem
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17 Feb 2016 11:57 #70282
by Boltonbrass
Replied by Boltonbrass on topic Re:How to enable EPP on PCI parallel port card
I am having a hard time determining if my par port card is my homing problem. Any suggestions.
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