USB / LPT converter : How can I manage LPT2 pins ?

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andre_luis

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usb to lpt converter

Hi All,

My LPT1 port of Laptop don´t works anynmore, and I intend to use a USB/LPT converter.

But, looking at CONTROL PANEL > SYSTEM > HARDWARE , despite I can see LPT2, at it PROPERTIES, doesn´t appear RESSOURCES tab, like bellow.

( That properties are from LPT1 )
**broken link removed**
This tab Ressources above, does not appear at LPT2 !!!

If I use standard functions to access port, I have to know base adress of port :

Code: 
#define LPT1 0x278 
outportb(LPT1, Value); 
Value= inportb(LPT1);

So, my question is : What base adress may I use at LPT2 ? ( Due is not possible to know it looking at LPT2 properties ).

Regards.
Andre.
 

lpt1 to usb

As far as I know, no usual USB LPT adapter emulates "legacy" printer port. They can't be used for applications needing direct access to port addresses.
 

usb to lpt2

Really ?

So, it makes no sense.

I´m not talking about converters wich create "printer device", but about a converter that create a LPT device. In that case, I can see both LPT1 and LPT2 at hardware manager.

Regards.
 

lpt1 usb

Do you know, which "USB-to-LPT" chip is used with your part? I have seen only USB converters that provide a LPT port without the option to control single bits, e.g. Prolific PL2305. They are operating a the higher level of IEEE 1284 bidirectional interface, which gives better performance with USB packetwize transmission. It could be however, that other manufacturers implement an additional legacy LPT (bitbang) interface and a driver with lpt register emulation.
But in contrast to a onboard or PCMCIA LPT interface, you can't have real hardware LPT registers through USB.
 

prolific usb to lpt

Do you know, which "USB-to-LPT" chip is used with your part?
Click to expand...

FvM,

The chipset is manufactured by : https://www.moschip.com
I believe it is used : **broken link removed**

So, it mean that I can´t use functions inportb, outportb anymore ?

Other point : I saw on web, a library called NPort, in wich it is possible to read adress of ports of PC. I´ll test it and report result here.

reagrds.

+++
 

usb lpt converter

Hello,

interestingly, MOSChip unlike prolific provides a mechanism for direct access to port hardware through vendor specific USB commands. This would allow emulation of a legacy LPT port by a driver. But I don't know if MOSChip provides a suitable driver. Furthermore, IO registers could only exist by IO virtualization, a rather complex and slow mechanism. It would not work with hardware kernel drivers.
As mentioned in another discussion, using a PCMCIA printer adapter is the only solution without serious limitations.

Regards,
Frank
 

usb to lpt chip

Hi Frank,

As mentioned above, I´m posting the test result here.

Unnafortunatelly, the program NPort was not capable to detect adress of LPT2. It even cannot see this port.

Thank you for answers.

+++
 

usb-lpt

Hi,

You might take a look at this: **broken link removed**

Regards,
Franck.
 

usb lpt2

Frank,

I had seen this webpage before, but the usage is very hard to understand.
Thank you anyway.

+++
 

usb to lpt1 converter

They working group basically has designed a series of USB to LPT converters that are said to be function compatible with legacy LPT ports, e.g. to connect programming cables. Looks like a profound design, but I didn't test it.
 

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