The following web site shows how to interface seven
segment LED's to a 89C2051 (an 8051 derivative)

Someone must have been hallucinating.
From the AT89c2051 deatasheet

VOH Output High-voltage
(Ports 1, 3)
IOH = -80 µA, VCC = 5V ± 10% 2.4 V
IOH = -30 µA 0.75 VCC V
IOH = -12 µA 0.9 VCC V

I have yet to see a 7 segment display that is visible driven by 80uA

Erik