I'm sorry about my question, I'm using 80C51, demultiplexer 4 to 16 in high nibble of port 3, to control the 10 columns of dot matrix (4 others output of demux not in use),Port 0 is used as current sink of dot matrix through the ULN, i'm using ULN 2803 to sink the current from dot matrix. The two dot matrix is in parallel in its row (7 row each), each have 5 column, so the total column is ten.

The seven segment is controlled from port 2, low nibble is used to inputs the BCD to seven segment, and the high nibble is used as control each seven segment (i use three digit, so p2.7 isn't used)

Port 1 is used as input from push-on-button(active low), i use 6 push-on-button. I want to display the dot matrix with many picture variable and sevent segment with its number in the same time, i also want to check out if the button is being pressed, so if there is any change in input button, either the dot matrix display and seven segment will change. i feel confuse with the assembly code that has to display the dot matrix and seven segment in the same time, and also checking the button. Any suggestion?

thanx...