Hello. I have the the Pong Game code in Verilog with FPGA Xilinx Spartan Basys2. Everything works well, but I notice some flickering in the monitor, something like vibrations. What do you think? What is the problem? Maybe noisy clock? Thank you.
In general, it's impossible to answer without your source code. But the Basys2 is well known in e.g. classic fpga computing for it's bad clock, more exactly, it's a jitty oscillator. This is often the source of pixel jittering. AFAIK the board has an 8-pin socket for an extra clock source.
if there is a pll used, the clock should be fine. small clock problems usually lead only to bad pixels. if there is flickering, a bad constellation between hsynch and vsynch is given usually most probably also a unsynched updating process of the screen will be the problem to solve