Hi,

I need to design a 8051 LED interface via a 8255. At first i directly connected the LED to port A of the 8255. The other side of the LED was connected to ground. when i wrote a program to move a byte '#FFH' to port A of the 8255,none of the 8 LEDs lit up. then i tried to use a driver (transistor) and executed the same program and in this case all the 8 LEDs lit up. So what is the problem?

thanks
george