MSP430F41x2
MIXED SIGNAL MICROCONTROLLER
SLAS648E -- APRIL 2009 -- REVISED MARCH 2011
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, literature number
SLAU056.
oscillator and system clock
The clock system in the MSP430F41x2 is supported by the FLL+ 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 an 8-MHz high-frequency crystal oscillator (XT1). The FLL+ clock module is designed to
meet the requirements of both low system cost and low power consumption. The FLL+ features a 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 s. The FLL+ module provides the following clock signals:
D
Auxiliary clock (ACLK), sourced from a 32768-Hz watch crystal, a high-frequency crystal, or a very
low-power LF oscillator
D
D
D
Main clock (MCLK), the system clock used by the CPU
Sub-Main clock (SMCLK), the sub-system clock used by the peripheral modules
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, VCC may not
have ramped to VCC(min) at that time. The user must insure the default FLL+ settings are not changed until VCC
reaches VCC(min). If desired, the SVS circuit can be used to determine when VCC reaches VCC(min)
.
digital I/O
There are seven 8-bit I/O ports implemented—ports P1 through P7. Port P7 is a 7-bit I/O port.
D
D
D
D
All individual I/O bits are independently programmable.
Any combination of input, output, and interrupt conditions is possible.
Edge-selectable interrupt input capability for all the eight bits of ports P1 and P2.
Read/write access to port-control registers is supported by all instructions.
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