WANTED - DAC for 15k scanner

[carmangary]

To test the DAC create two images that you can run with your software. One with a horizontal line in the middle of the screen and one with a vertical line in the middle of the screen.

When you run the horizontal pattern the DAC Y signal should stay constant at around 2.5VDC. When you run the vertical picture the DAC X signal should stay constant at around 2.5V. Don't fool with trying to test with any other shapes with a digital multimeter because the signals will be changing faster than your display and you won't be able to tell anything. Test this on your tower since you know the LPT port is standard. If you can get it working then move on to your laptop.

As far as your laptop goes, go into Device Manager and find the port. Right click on it and select properties. Then click on the Resources tab and see what the resource settings for it. Report back.

Don't give up too quickly... that always results in wasting a lot of money for nothing.

[cruch]

printer mode is "spp" and I guess it was hex 378?
To change printer mode, you must go in to the bios.

Usually it is keboard "DEL" in PC's. It is differ on laptops..

Maby this solve the problem ?

This has to be correct when I used the alphalite

[andy_con]

ive been told by a computer god, that a usb to parallel would work, providing you get the right one.

apparently most usb to parallel dont use all the 25 pins but some use all 25 pins and that would work fine.

anyone???

[yaddatrance]

Actually, a USB to parallel is unlikely to work (at least in the way you would expect it to)... Those enumerate as HID printer driver class and does not correspond to normal IO addressing for bit-banging.

I note the Toshiba-ish breakout... you may not be generating high enough voltage on the parallel port. I would make a voltage "booster" using a couple 74LS245 octal tranceiver (or a 74LS244 if the system doesn't require bidir mode)...

P.S. if you just want to buy something and get it over with, buy a PCMCIA parallel port card... IEEE1284 standard cards are pretty cheap.

[andy_con]

Actually, a USB to parallel is unlikely to work (at least in the way you would expect it to)... Those enumerate as HID printer driver class and does not correspond to normal IO addressing for bit-banging.

I note the Toshiba-ish breakout... you may not be generating high enough voltage on the parallel port. I would make a voltage "booster" using a couple 74LS245 octal tranceiver (or a 74LS244 if the system doesn't require bidir mode)...

P.S. if you just want to buy something and get it over with, buy a PCMCIA parallel port card... IEEE1284 standard cards are pretty cheap.

he did also say about a pcmcia card

cheers mate