Datasheet

MSP430F21x2
SLAS578J –NOVEMBER 2007– REVISED JANUARY 2012 www.ti.com
Peripherals
Peripherals are connected to the CPU through data, address, and control buses and can be handled using all
instructions. For complete module descriptions, see the MSP430x2xx Family User's Guide (SLAU144).
Oscillator and System Clock
The clock system is supported by the basic clock module that includes support for a 32768-Hz watch crystal
oscillator, an internal very-low-power low-frequency oscillator, an internal digitally-controlled oscillator (DCO), and
a high-frequency crystal oscillator. The basic clock module is designed to meet the requirements of both low
system cost and low power consumption. The internal DCO provides a fast turn-on clock source and stabilizes in
less than 1 µs. The basic clock module provides the following clock signals:
• Auxiliary clock (ACLK), sourced from a 32768-Hz watch crystal, a high-frequency crystal, or the internal
very-low-power LF oscillator.
• Main clock (MCLK), the system clock used by the CPU.
• Sub-Main clock (SMCLK), the sub-system clock used by the peripheral modules.
The DCO settings to calibrate the DCO output frequency are stored in the information memory segment A.
Calibration Data Stored in Information Memory Segment A
Calibration data is stored for both the DCO and for ADC10 organized in a tag-length-value (TLV) structure.
Table 12. Tags Used by the ADC Calibration Tags
NAME ADDRESS VALUE DESCRIPTION
TAG_DCO_30 0x10F6 0x01 DCO frequency calibration at V
CC
= 3 V and T
A
= 30°C at calibration
TAG_ADC10_1 0x10DA 0x08 ADC10_1 calibration tag
TAG_EMPTY - 0xFE Identifier for empty memory areas
Table 13. Labels Used by the ADC Calibration Tags
ADDRESS
LABEL CONDITION AT CALIBRATION / DESCRIPTION SIZE
OFFSET
CAL_ADC_25T85 INCHx = 0x1010, REF2_5 = 1, T
A
= 85°C word 0x0010
CAL_ADC_25T30 INCHx = 0x1010, REF2_5 = 1, T
A
= 30°C word 0x000E
CAL_ADC_25VREF_FACTOR REF2_5 = 1, T
A
= 30°C, I
VREF+
= 1 mA word 0x000C
CAL_ADC_15T85 INCHx = 0x1010, REF2_5 = 0, T
A
= 85°C word 0x000A
CAL_ADC_15T30 INCHx = 0x1010, REF2_5 = 0, T
A
= 30°C word 0x0008
CAL_ADC_15VREF_FACTOR REF2_5 = 0, T
A
= 30°C, I
VREF+
= 0.5 mA word 0x0006
CAL_ADC_OFFSET External V
REF
= 1.5 V, f
ADC10CLK
= 5 MHz word 0x0004
CAL_ADC_GAIN_FACTOR External V
REF
= 1.5 V, f
ADC10CLK
= 5 MHz word 0x0002
CAL_BC1_1MHz - byte 0x0009
CAL_DCO_1MHz - byte 0x0008
CAL_BC1_8MHz - byte 0x0007
CAL_DCO_8MHz - byte 0x0006
CAL_BC1_12MHz - byte 0x0005
CAL_DCO_12MHz - byte 0x0004
CAL_BC1_16MHz - byte 0x0003
CAL_DCO_16MHz - byte 0x0002
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