lectric
Newbie level 3
Built 74HC5051 mux and am now testing the parallel port's I/O. Connected anodes of 3 LEDs to pins 2-4 of female DB25. Ran cathodes together to a 1k resistor which is connected to ground (pin 25).
Program (classic C) displays decimal 249-255 (11111001-11111111) so that pins 2-4 will be the channel (8) select pins. There is a 5 second delay between changes to this signal.
Problem: all LEDs light regardless.
I would expect even if wrong somewhere this would blink. Anyone see my mistake in electronic wiring?
Program (classic C) displays decimal 249-255 (11111001-11111111) so that pins 2-4 will be the channel (8) select pins. There is a 5 second delay between changes to this signal.
Problem: all LEDs light regardless.
I would expect even if wrong somewhere this would blink. Anyone see my mistake in electronic wiring?
