[time-nuts] OT - USB to LPT Adapter - Does it exist?

[Jim Stephens]

On 1/11/2013 8:46 AM, Chris Albertson wrote:
> On Fri, Jan 11, 2013 at 5:09 AM, J. L. Trantham <jltran at att.net> wrote:
>
>> My goal is to connect a parallel port chip programmer via USB but the
>> software only looks for LPT ports.  It works with PCMCIA to parallel port
>> adapters but I haven't solved the puzzle yet with a USB connected device.
>>
>
> I think the best solution is to finally retire that old  parallel port chip
> programmer and replace it with something more modern.  You might have paid
> a lot for it but today $35 will get you something with a USB cnetion and
> then you don't need the printer port.
>
>
>
> Chris Albertson
> Redondo Beach, California
Chris,
there are programmers out right now that include the parallel port 
bitbanging feature.  Old isn't part of the equation.

They are identified with the "willem" in the title in some cases. The 
one I have derives the power for the logic to run the board and oversee 
the programmer from a USB connection.  The data to and from the device 
is sent via the parallel port to a PC with the software.

Power for programming comes from a wall wart.

The parallel port must be a physical LPT port as mentioned here, on the 
PC because of timing issues.  I don't think the programming timing is 
done by the board, but by the PC's code banging the port.

Many discussions here all have touched on how good you can rely on 
timing when USB is involved, so I doubt if the USB extenders will work 
very well.  People who have tried may comment here, but I would not go 
down that path.

A higher cost fully standalone USB attached device is the other 
alternative, but would probably still require its own power as well to 
get the programming voltages and currents required.  What comes down the 
USB port probably would not be enough.  That is a bit off topic, but 
worth mentioning.  I am commenting on full capability prom programmers 
which will program a wide variety of devices.  If you had to make a USB 
dongle to program a specific device you might get away with it.  However 
to handle large devices which require high speed to get them programmed 
in a reasonable time period would probably need more power.
Jim

http://www.ebay.com/itm/261149380462