MSP430F54系列UCS時(shí)鐘

XT1CLK：可以用于低頻率的32.768KHZ或者4~32MHZ的頻率。但不是每一個(gè)設備都支持高頻率的，有些只支持32.768KHZ。

VLOCLK：內部低功耗，低頻率的時(shí)鐘，典型值為10KHZ。

REFOCLK：內部時(shí)鐘，典型值32.768KHZ。

DCOCLK: Internal digitally-controlled oscillator (DCO) that can be stabilized by the FLL。

XT2CLK：高頻時(shí)鐘源，外部時(shí)鐘，4 MHz到32 MHz。

2：我們可用的從UCS模塊出來(lái)的3個(gè)時(shí)鐘：

ACLK:輔助時(shí)鐘。

MCLK：主時(shí)鐘。

;SMCLK：系統子時(shí)鐘。

3：時(shí)鐘操作:

After a PUC, the UCS module default configuration is:
1） XT1 in LF mode is selected as the oscillator source for XT1CLK. XT1CLK is selected for ACLK.
2） DCOCLKDIV is selected for MCLK.
3） DCOCLKDIV is selected for SMCLK.
4） FLL operation is enabled and XT1CLK is selected as the FLL reference clock, FLLREFCLK.
5 ）XIN and XOUT pins are set to general-purpose I/Os and XT1 remains disabled until the I/O ports are
configured for XT1 operation.
6 ）When available, XT2IN and XT2OUT pins are set to general-purpose I/Os and XT2 is disabled.

4：設置時(shí)鐘的相關(guān)寄存器：

UCSCTL0~UCSCTL8。