Texas Instruments MSP430x1xx - Manual (Page 119)

Basic Clock Module Control Registers
7-19
Basic Clock Module
Bit6, XTS: The LFXT1 oscillator operates with a low-frequency clock
crystal or with a high-frequency crystal:
XTS = 0:
The low-frequency oscillator is selected.
XTS = 1: The high-frequency oscillator is selected.
The oscillator selection must meet the external crystal’s operating condition.
Bit7, XT2Off: The XT2 oscillator is switched on or off:
XT2Off = 0: the oscillator is on
XT2Off = 1: the oscillator is off if it is not used for MCLK or SMCLK.
BCSCTL2 is affected by a valid PUC or POR condition.
7 0
rw–(0) rw–(0) rw–(0) rw–(0) rw–0 rw–0 rw–0 rw–0
058h
BCSCTL2
DCOR DIVS.0 DIVS.1 DIVM.1 DIVM.0 SELS SELM.1 SELM.0
Bit0, DCOR: The DCOR bit selects the resistor for injecting current into the
dc generator. Based on this current, the oscillator operates if acti-
vated.
DCOR = 0: Internal resistor on, the oscillator can operate. The fail-
safe mode is on.
DCOR = 1: Internal resistor off, the current must be injected
externally if the DCO output drives any clock using
the DCOCLK.
Bit1, Bit2: The selected source for SMCLK is divided by:
DIVS.1 .. DIVS.0 DIVS = 0: 1
DIVS = 1: 2
DIVS = 2: 4
DIVS = 3: 8
Bit3, SELS: Selects the source for generating SMCLK:
SELS = 0: Use the DCOCLK
SELS = 1: Use the XT2CLK signal (in three-oscillator systems)
or
LFXT1CLK signal (in two-oscillator systems)
Bit4, Bit5: The selected source for MCLK is divided by:
DIVM.0 .. DIVM.1 DIVM = 0: 1
DIVM = 1: 2
DIVM = 2: 4
DIVM = 3: 8
Bit6, Bit7: Selects the source for generating MCLK:
SELM.0 .. SELM.1 SELM = 0: Use the DCOCLK
SELM = 1: Use the DCOCLK
SELM = 2: Use the XT2CLK (x13x and x14x devices) or
Use the LFXT1CLK (x11x(1) devices)
SELM = 3: Use the LFXT1CLK