crystal control register
| XTAL_XCUR_BOOST_REG | 1 to increase 16/32 MHz xtal current |
| XTAL_BPXDLY | Bypass the power up delay in the XTAL core. |
| XTAL_BP_HYSRES_REG | 1 to bypass the degeneration resistor in order to reduce the hysteresis voltage |
| XTAL_XSMT_EN_REG | 1 to use hysteresis buffer |
| XTAL_XRDY_REG | 1 to set xtal ready signal by register |
| XTAL_XOUT_DIS_REG | 1 not to send 16/32 MHz xtal clk out |
| DIV_DIFF_CLK_DIG_DIS | disable differential clock of digital |
| XTAL_SU_CB_REG | Register controlled load cap of the XTAL_B in speed up modeCB=2pF+0.35pFSU_CB+5pFXADD_C |
| XTAL_SU_CA_REG | Register controlled load cap of the XTAL_A in speed up modeCA=2pF+0.35pFSU_CA+5pFXADD_C |
| XTAL_INV | Inverse crystal clock |
| XTAL_DIV | Divide crystal clock when external crystal is 32M this bit should be configured into 1 otherwise 0. |