External crystal n non-polar capasitor on 8051?

can anyone tell me what the function of 12mhz xtal n non-polar (30pF) on 8051?? n how they works?? thx

Well there is actually no document that can explain why two caps are connected... but as far as i know.. the reason for connecting caps is..

Due to continious working crystal saturates and these caps bypasses noise and does not allow crystal to saturate

This is what i know... if anyone else have any info regarding this.. please share.. thanks!