Any reply must be vague, since the question was it also !

Nobody can look into your head !


If you read my former post, there are at least minimal four main families **89C51**:

T89C51
AT89C51
IS89C51
P89C51

with a lot of different suffixes to specify one member of this family.
And until now nobody knows, which you mean.

But I think, there must be a data sheet available on the web for your secret 89C51 derivate.
Furthermore you need the data sheet of your LEDs to know, which current was needed for the wanted brightness.
And then you can determine, how many LEDs can be connected or if driver circuits are needed.


Peter