parallel port screwed?

one day, I accidently connected 12V to 5V when dealing with my microcontroller programmer. This has made the computer think that now the printer is out of paper when no printer is attached. This must indicate that a pull-down resistor or a wire is broken on the motherboard.

It seems that the data transmits properly from the port to the chip, but after further investigation, the strobe line is not patient enough for the BUSY line to go low.

Is it legal for the computer to have busy set to high and have the strobe low at the same time?

my ACK line is set low.

I would have thought there's no doubt you've blown your parallel port, it's a common problem when using it for interfacing - you need to be EXTREMELY careful not to abuse it - sticking 12V up it comes under the heading of severe abuse :lol:

In older machines this only involved popping another cheap card in the computer, but anything remotely modern has the port integrated in the motherboard (usually in a huge great chip), so a repair requires replacing the motherboard. You might consider adding an extra parallel port card, which would be considerably cheaper than a new motherboard, but they do tend to use peculiar addresses, which might make your interfacing more difficult?.