Andy:

I can light 7 segment display or multiplexed displays. My problem is bcd code which ports on p1 are being used for the 7 segment display.

Display 1 is p3.3
Display 2 is p3.4
Display 3 is p3.5

That turns on each display, however what ports in p1 are used for the bcd output. If Dan is using bcd like I would use with 7448 then I only need a,b,c,and d on driver chip.
If this the case what part of p1 is being used I don't see it in his source code.

With the 89c2051 port 1 is the following:
pin12 p1.0
pin13 p1.1
pin14 p1.2
pin15 p1.3
pin16 p1.4
pin17 p1.5
pin18 p1.6
pin19 p1.7

Is he using p1.0,p1.1,p1.2. and p1.3?
Or is he using p1.4,p1.5,p1.6, and p1.7

Or am I completely wrong with this idea?
That's why I ask for help from 8052 members.
I have only ask ten questions in last 3 years.

I also know that 89c2051 can drive the display if 20ma with out
transistors help. So should be able to drive displays with limiting resistors with out any trouble.

Refer to link:

http://www.8052.com/forum/read.phtml?id=127800

Thanks for reading this long post.

Best reguards,

Ralph Sack