MSP430F5172_16 Datasheet, PDF (58/117 Pages) Texas Instruments – Mixed-Signal Microcontrollers

MSP430F5172, MSP430F5152, MSP430F5132
MSP430F5171, MSP430F5151, MSP430F5131
SLAS619P – AUGUST 2010 – REVISED MAY 2016
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6.9.3 Oscillator and System Clock
The clock system (Unified Clock System [UCS]) module includes support for a 32-kHz watch crystal
oscillator and high-frequency crystal oscillator, an internal very-low-power low-frequency oscillator (VLO),
an internal trimmed low-frequency oscillator (REFO), and an integrated internal digitally controlled
oscillator (DCO). The UCS module is designed to meet the requirements of both low system cost and low
power consumption. The UCS module features digital frequency locked loop (FLL) hardware that, in
conjunction with a digital modulator, stabilizes the DCO frequency to a programmable multiple of the
watch crystal frequency. The internal DCO provides a fast turnon clock source and stabilizes in less than
5 µs. The UCS module provides the following clock signals:
• Auxiliary clock (ACLK), sourced from a 32-kHz watch crystal or high-frequency crystal (XT1), the
internal low-frequency oscillator (VLO), the trimmed low-frequency oscillator (REFO), or the internal
digitally-controlled oscillator DCO.
• Main clock (MCLK), the system clock used by the CPU. MCLK can be sourced by same sources
available to ACLK.
• Sub-Main clock (SMCLK), the subsystem clock used by the peripheral modules. SMCLK can be
sourced by same sources available to ACLK.
• ACLK/n, the buffered output of ACLK, ACLK/2, ACLK/4, ACLK/8, ACLK/16, ACLK/32.
6.9.4 Power-Management Module (PMM)
The PMM includes an integrated voltage regulator that supplies the core voltage to the device and
contains programmable output levels to provide for power optimization. The PMM also includes supply
voltage supervisor (SVS) and supply voltage monitoring (SVM) circuitry, as well as brownout protection.
The brownout circuit is implemented to provide the proper internal reset signal to the device during power-
on and power-off. The SVS/SVM circuitry detects if the supply voltage drops below a user-selectable level
and supports both supply voltage supervision (the device is automatically reset) and supply voltage
monitoring (SVM, the device is not automatically reset). SVS and SVM circuitry is available on the primary
supply and core supply.
6.9.5 Hardware Multiplier
The multiplication operation is supported by a dedicated peripheral module. The module performs
operations with 32-bit, 24-bit, 16-bit, and 8-bit operands. The module is capable of supporting signed and
unsigned multiplication as well as signed and unsigned multiply and accumulate operations
6.9.6 Watchdog Timer (WDT_A)
The primary function of the watchdog timer (WDT_A) module is to perform a controlled system restart
after a software problem occurs. If the selected time interval expires, a system reset is generated. If the
watchdog function is not needed in an application, the module can be configured as an interval timer and
can generate interrupts at selected time intervals.
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Detailed Description
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