Texas Instruments MSP430x1xx - Manual (Page 103)

7-3
Basic Clock Module
The Basic Clock Module includes two or three clock sources:
- LFXT1CLK low-frequency/high-frequency clock source. One oscillator
that can be used with low-frequency watch crystals, standard crystals,
resonators, or external clock sources. See the device data sheet for the
exact operating frequency range.
- XT2CLK high-frequency clock source. This optional high-frequency
oscillator can also use standard crystals, resonators, or external clock
sources in the 450-kHz to 8-MHz range. See the device data sheet for the
exact operating frequency range and availability of this optional oscillator.
- DCOCLK clock source. One digitally controlled oscillator (DCO) with
RC-type characteristics.
Three clock signals are available from the Basic Clock Module:
- ACLK auxiliary clock. The ACLK is the buffered LFXT1CLK clock source
divided by 1, 2, 4, or 8. Software selects the division factor. ACLK is
software selectable for individual peripheral modules.
- MCLK master clock. MCLK is software selectable as LFXT1CLK, XT2CLK
(if available), or DCOCLK. MCLK is divided by 1, 2, 4, or 8. Software se-
lects the division factor. MCLK is used by the CPU and system.
- SMCLK submain clock. SMCLK is software selectable as LFXT1CLK,
XT2CLK (if available), or DCOCLK. SMCLK is divided by 1, 2, 4, or 8. Soft-
ware selects the division factor. SMCLK is software selectable for individu-
al peripheral modules.