2 device initial conditions after system reset, Software initialization – Texas Instruments MSP430x4xx User Manual

Page 22

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System Reset and Initialization

2-4

System Resets, Interrupts, and Operating Modes

2.1.2

Device Initial Conditions After System Reset

After a POR, the initial MSP430 conditions are:

-

The RST/NMI pin is configured in the reset mode.

-

I/O pins are switched to input mode as described in the Digital I/O chapter.

-

Other peripheral modules and registers are initialized as described in their
respective chapters in this manual.

-

Status register (SR) is reset.

-

The watchdog timer powers up active in watchdog mode.

-

Program counter (PC) is loaded with address contained at reset vector
location (0FFFEh). CPU execution begins at that address.

Software Initialization

After a system reset, user software must initialize the MSP430 for the
application requirements. The following must occur:

-

Initialize the SP, typically to the top of RAM.

-

Initialize the watchdog to the requirements of the application.

-

Configure peripheral modules to the requirements of the application.

Additionally, the watchdog timer, oscillator fault, and flash memory flags can
be evaluated to determine the source of the reset.

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