I'm doing a parallel port exercise trying to light up leds. I'm using WIN98 with a parallel port that is integrated into the motherboard. The parallel port is set to SPP mode in the BIOS.
The problem is that I'm not able to turn the leds on or off as expected.
I'm using vbOut 888, 0 to turn off all the leds and vbOut 888, 255 to turn all the leds on.
An example of an unexpected result is calling vbOut 888, 0 and pins 1,2, 4 and 4 are still lighting up the led.
I am using pins 2-9 in my attempt to light the leds.
Which pins should be putting out about +5v all the time?
If I reboot the computer pin2 keeps the led lit all the time through the reboot process. I haven't tested the other pins during the reboot process.
Any advice is apprecitated.
It may be a loading problem, try using a high impedance load instead of relatively high current LED's. This site is also very helpfull http://www.lvr.com/files/ibmlpt.txt
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