Datasheet

MSP430xG461x
MIXED SIGNAL MICROCONTROLLER
SLAS508I − APRIL 2006 − REVISED MARCH 2011
18
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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 MSP430x4xx Family User’s Guide (SLAU056).
DMA controller
The DMA controller allows movement of data from one memory address to another without CPU intervention.
For example, the DMA controller can be used to move data from the ADC12 conversion memory to RAM. Using
the DMA controller can increase the throughput of peripheral modules. The DMA controller reduces system
power consumption by allowing the CPU to remain in sleep mode without having to awaken to move data to
or from a peripheral.
oscillator and system clock
The clock system in the MSP430xG461x family of devices is supported by the FLL+ module, which includes
support for a 32768-Hz watch crystal oscillator, an internal digitally controlled oscillator (DCO), and a
high-frequency crystal oscillator. The FLL+ clock module is designed to meet the requirements of both low
system cost and low power consumption. The FLL+ 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 turn-on clock source and stabilizes in less than 6 μs. The
FLL+ module provides the following clock signals:
D Auxiliary clock (ACLK), sourced from a 32768-Hz watch crystal or a high frequency crystal
D Main clock (MCLK), the system clock used by the CPU
D Sub-Main clock (SMCLK), the subsystem clock used by the peripheral modules
D ACLK/n, the buffered output of ACLK, ACLK/2, ACLK/4, or ACLK/8
brownout, supply voltage supervisor
The brownout circuit is implemented to provide the proper internal reset signal to the device during power-on
and power-off. The supply voltage supervisor (SVS) 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).
The CPU begins code execution after the brownout circuit releases the device reset. However, V
CC
may not
have ramped to V
CC(min)
at that time. The user must insure the default FLL+ settings are not changed until V
CC
reaches V
CC(min)
. If desired, the SVS circuit can be used to determine when V
CC
reaches V
CC(min)
.
digital I/O
There are ten 8-bit I/O ports implemented—ports P1 through P10:
D All individual I/O bits are independently programmable.
D Any combination of input, output, and interrupt conditions is possible.
D Edge-selectable interrupt input capability for all the eight bits of ports P1 and P2.
D Read/write access to port-control registers is supported by all instructions.
D Ports P7/P8 and P9/P10 can be accessed word-wise as ports PA and PB respectively.
Basic Timer1 and Real-Time Clock
The Basic Timer1 has two independent 8-bit timers that can be cascaded to form a 16-bit timer/counter. Both
timers can be read and written by software. Basic Timer1 is extended to provide an integrated real-time clock
(RTC). An internal calendar compensates for months with less than 31 days and includes leap-year correction.