Hi,

If you to connect a LED to any port of c51 family and want a brightness without
using any driver, you should connect the anod of the LED to +5V over a 220ohm resistor and connect the katod directly to the pin you are going to use.

if you set the this pin (+5V), then LED is off; if you CLR this pin, your LED will light.

8051 family ports are relatively stronger logic low, (sinking capability) then of logic high (sourcing)

Rustu