Freescale recommends use of a blocking cap with the MC9S12DP256 Colpits clock circuit. The cap blocks DC voltage between Extal and the crystal. It is referred to as C11 in the Developer User's Guide (V2.05). What is a recommended value for C11 if the device is using a 16 MHz crystal with 18 pF caps? Apparently this cap is recommended to limit DC voltage applied to the crystal (thereby reducing crystal life expectancy) and minimizing startup issues.