Author Topic: Parallel JTAG Adapter to USB  (Read 26079 times)

enliteneer

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Parallel JTAG Adapter to USB
« on: November 09, 2010, 08:05:49 pm »
All of the Parallel to USB Bridge devices/cables I've found are either intended to be used with a printer, or don't work on winXP/Win7
( usbgear.net/item_157.html, lpt2usb.net   )

The problem is, I have a parallel port jtag debugger on WinXp and I don't have a parallel port!    There's tons of USB to I/O solutions (Cypress, FTDI, etc), so I'm not sure why this isn't possible.

It would seem that if your usb adapter can read/write I/Os, not full speed since bit-banged, then it can generate EPP/ECP/SPP/BPP.   Perhaps would the tricky part be the usb driver?  It would have to intercept I/O read/write calls to 0x378 and route them instead to the DB25...    But even this doesn't seem totally impossible...   what am I missing?



Jan Axelson

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Re: Parallel JTAG Adapter to USB
« Reply #1 on: November 10, 2010, 12:59:13 am »

Guido Koerber

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Re: Parallel JTAG Adapter to USB
« Reply #2 on: November 10, 2010, 05:37:12 pm »
This is going to be couple orders of magnitude slower than a real parallel port. And as you already said you would need to intercept I/O address accesses and channel them through USB.

I think the only realistic options are to either get a real parallel port into your machine, or replace the device.