Setting up DCO and external clocks

To set up the DCO and external clocks, click on the Setup DCO and XT Clocks button in the MSP430 Config dialog.

MSP430 1xx, 2xx, and 20xx subtypes

DCO

BCSCTL1.RSELx: Defines a nominal frequency in conjunction with the DCOCTL.DCOx and DCOCTL.MODx. See also Texas Instruments MSP430X1 User Guide.

DCOCTL.DCOx: Defines a nominal frequency in conjunction with the BCSCTL1.RSELx and DCOCTL.MODx. See also Texas Instruments MSP430X1 User Guide.

DCOCTL.MODx: Defines a nominal frequency in conjunction with the DCOCTL.DCOx and BCSCTL1.RSELx. See also Texas Instruments MSP430X1 User Guide.

DCO Speed: This is a read-only setting. It calculates the DCO speed based on either the factory calibrated setting or the user-specified calibrated setting, determined by the RSELx, DCOx, and MODx settings.

Use Calibrated Setting: Only for 2xx. Uses factory calibrated setting for the DCO.

LFXT1

Capacitance: Specifies the value of desired on-chip capacitance.

Crystal Resonator ranges: Higher frequency ranges supported by the 2xx, external.

Crystal Speed: Specifies the speed of external crystal one.

High Frequency Mode: Sets to true if LFXT1 is greater than or equal to 400 kHz.

Source: For 2xx subtypes, you can specify the source of the XT1 clock. The XTI clock source can be external or internal. Your choices are:

32768 Hz crystal: Standard low frequency, external
VLOCLK
:
Very low frequency, internal
Reserved:
Do not use
Digital clock: Digital oscillator (not crystal), external
Digital 0.4: Digital oscillator (not crystal), external

XT2

Crystal Speed: Specifies the speed of the second external crystal. If this value is 0, Embed assumes there is not a second external oscillator.

Range: Specifies the frequency range for the second external crystal.

The MSP430 FLL+  Config dialog

This dialog lets you configure settings for the MSP430 3xx and 4xx subtypes.

FLL

Additional Multiplier: Specifies an additional multiplier for calculating the DCO speed.

DCO Speed: Indicates the DCO speed, which is based on the Multiple of Crystal Freq and Additional Multiplier values.

Multiple of Crystal Freq: Indicates the multiple of crystal frequency. It defines the DCO speed by multiplying this value by the crystal speed.

LFXT1

Capacitance: Specifies the value of desired on-chip capacitance.

Crystal Speed: Specifies the speed of external crystal one.

High Frequency Mode: Sets to true if LFXT1 is greater than or equal to 400 kHz.

XT2

Crystal Speed: Specifies the speed of the second external crystal. If this value is 0, Embed assumes there is not a second external oscillator.

The MSP430 Unified Clock System (UCS) dialog

This dialog lets you configure settings for the MSP430 5xx subtypes.

FLL

DCOCLK: Scaled version of DCOCLKDIV.

DCOCLKDIV: Read-only value, based on the FLL Reference Clk Src, FLL Reference Clk Div, and Multiple of Crystal Freq values.

FLLD Prescaler: Applies a scale factor to the DCOCLK.

FLL Reference Clk Src: Selects the clock source for the frequency lock loop to calculate the value of DCOCLKDIV.

FLL Reference Clock Div: Divides the clock source to calculate the value of DCOCLKDIV.

Multiple of Crystal Freq: Multiples the clock source to calculate the value of DCOCLKDIV.

XT1

Crystal Speed: Specifies the speed of external crystal one.

Use External Clock: Specifies an external clock.

Turn Off in LPM4: Turns off crystal one in low-power mode four.

Use On-Chip Capacitance: Makes on-chip capacitance externally available. Select the capacitance from the drop-down box.

XT2

Crystal Speed: Specifies the speed of the second external crystal. If this value is 0, Embed assumes there is not a second external oscillator.

Turn Off in LPM4: Turns off crystal two in low power mode four.