Datasheet

MSP430F23x0
MIXED SIGNAL MICROCONTROLLER
SLAS518A -- AUGUST 2006 -- REVISED MAY 2007
12
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
peripherals
Peripherals are connected to the CPU through data, address, and control busses and can be handled using
all instructions. For complete module descriptions, refer to the MSP430x2xx Family User’s Guide.
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:
D Auxiliary clock (ACLK), sourced from a 32768-Hz watch crystal, a high frequency crystal or the internal very
low power LF oscillator.
D Main clock (MCLK), the system clock used by the CPU.
D 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.
DCO Calibration Data (provided from factory in flash info memory segment A)
DCO Frequency Calibration Register Size Address
1MHz
CALBC1_1MHZ byte
0x10FF
CALDCO_1MHZ byte
0x10FE
8MHz
CALBC1_8MHZ byte
0x10FD
CALDCO_8MHZ byte
0x10FC
12 MHz
CALBC1_12MHZ byte
0x10FB
CALDCO_12MHZ byte
0x10FA
16 MHz
CALBC1_16MHZ byte
0x10F9
CALDCO_16MHZ byte
0x10F8
brownout
The brownout circuit is implemented to provide the proper internal reset signal to the device during power on
and power off.
digital I/O
There are 4 8-bit I/O ports implemented—ports P1 through P4:
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 Each I/O has an individually programmable pull--up/pull--down resistor.
The MSP430F23x0 devices provide 32 total port I/O pins available externally. Please see the device pinout for
more information.
watchdog timer +
The primary function of the watchdog timer (WDT+) 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.