USB to Parallel adapter?

Hello Terry,

Walmart has one that is claimed to be bidirectional. No idea how compatible it would be in this case:

If you don't have Walmwart stores there are some in Germany.

"Walmwart" is what I call them too ;-)

...Jim Thompson

I had the same problem with a Velleman (PCS500) scope. I ended up with a PCIMIA card to give me a real LPT port. That also works for my Xilinx cable too. No cheaper though.

I originally got a usb to parallel adaptor which said it was IEEE1284 (or some number), bidirectional. Good enough I thought but it wasn't. No drivers except for printers and not all printers work either so I now read.

Personally I'd go for the real LPT route as it works with more stuff.

I do not know if you have an equivalent of "Radioshack" in the UK, but if so, try buying a USB to parallel adapter, and return it if it does not work. There is no risk for you.

I had a similar issue with a laptop and SERIAL port, and a Radioshack adapter worked. (and the one I bought new from ebay for 6 times less did not work).

Hello Jim,

I don't like much going there because of their slow lines. But when it comes to mundane stuff such as pool chlorine their prices are hard to beat. And their Kilz paint is quite good and reasonably priced.

It's also a good place to browse the toy and computer sections for ideas on who to make electronics cheaper.

"on who to make electronics cheaper" Eh..? ;)

Why is it unreliable?

Try re-formatting and installing Windows 2000. Failing that, make sure the CPU has sufficient thermal paste (I learned this the hard way!), and make sure the RAM is seated properly.

Try running Prime95's torture test overnight too.

Michael

Ahem, "how". But "who" is also an interesting topic. Sometimes it's good to buy something and look what brand of LCD they used, and so on.

Almost zero. The key is that the adapters should not really be described as 'USB to parallel' adapters, but as _printer_ adapters. They perform the operations associated with operation of the parallel port as a printer control device, fine. However they lack the abilities present in the 'real' port, where bits can be set/cleared/read at relatively precise times. It is actually good, that Pico have an adapter. Otherwise you would need to look at the cost of a PCMCIA parallel printer card instead. The same problem is present for things like many old scanners, homebrew milling machines, and some cameras, using the parallel port, which the 'off the shelf' USB adapters, will not drive.

Best Wishes

Business grade laptops often have parallel ports (but more $$$). I'd just get the old computer running again, or get a new fast box and put a parallel port card in it. The USB to parallel adapters only work with printers (no bit banging).

I would think that one of you bit-bangers could design a USB-to-LPT device and then write software to take parallel port commands and convert them to USB (and back). No?

...Jim Thompson

Hello Jim,

I was told by a (pretty good) Windows programmer that such a task of near realtime control via USB can quickly turn into a major nightmare. Deadline is near, stuff don't work, coffee, more coffee, Prozac...

You have to deal with numerous intricacies of Windows, a product that isn't exactly known for flawlessness. Plus I guess the market potential for a bitbang capable device would be slim.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

There would be timing issues with the USB stack, plus you couldn't work around the timing issues with out knowing what they would be. But you could create a stack that could handle the timing for you, sort of extended instruction set. Then Open source publish it. I'm sure someone will write one, as the Parallel port is next on the list for obsolesance.

Cheers

So bit-bangers aren't up to analog-level design ?:-)

...Jim Thompson

Even if you got a new laptop with a parallel port, the O-scpoe software might not work with it. Hardware timing with XP will probably not be as quick and acurate as with win98, and the software may not have proper drivers to work with XP. I've got aToshiba laptop with a parallel port, and I haven't been able to bitbang it as of yet.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Actually the USB bus is time sliced at 1ms chunks, so even the best case would be a 2ms + pulse when bit banging. A far cry from DOS and a fast PCI port. Thats why most attempts fail. You need smarts in the adaptor, but that affects copmpatibility.

Cheers

Basically, the problem is that XP is a real operating system. 98 will happily drop down into a mode very much like DOS. XP will not; XP never gets out of the picture. That is why XP is considerably less crash-prone than 98.

Many thanks for all those helpful replies. Quite a bit to think about.

Getting the old W98 PC working reliably (perhaps under an alternative OS such a W2000 as Michael suggests) certainly seems the most cost effective solution. But, apart from its current unreliability, and my unwillingness to invest much more time on it, two other factors favouring a laptop are

- Space; the 17" Ilyama and the largish PC tower would release some handy room

- I'd like to play with the laptop in house and garden. (Although this will inevitably increase hassle from my wife about spending too long at my computer already ).

A guy sat down opposite me on the train and opened up his HP laptop - which had a parallel port. He reckoned it was "a year or so old." So I'd think seriously about an older notebook, but for the warnings that even that might not work.

Look closely, some brand new laptops have the parallel port, but they most often are in the "desktop replacement" category.