need help- random numbers 0-3

Hey,

My project is a game that lunches 4 balls up and it shown in UART (640X480), the clk in is 50 MHZ.

My problem is a machine that enabling 1 ball in every 1 second in random.

Also if I enabling 1 ball and that machine enabling me the same ball again it cuts that ball and it sends it to the start. How can i make it see 2 ball on the UART?

Another problem I have is a detector, instead of pushing button number 1 for ball number 1 I want that if I click on number 1 on PS2 it will do the same work on ball number 1 (like the button).

hope you can help me.

thx!

:)