Harvest moon friends of mineral town help!

[9WA]

I can't get any of the codebreakers or gamesharks to work. I've tried using european and US version roms but it still doesn't work. I'm not a noob to this. I've used cheats for lots of games but my methods doesn't seem to work. I use visual boy advance.

Any help will be appreciated.

[9WA]

I found out how to use the codebreaker. No thanks to you guys!