实验4_wdt.s43

MSP-TEST44X 学习板光盘资料及实验说明 本学习板是按照教育大纲

#include  "msp430x44x.h"
;******************************************************************************
;   MSP-Test44x  Demo - WDT Toggle P5.1 Interval overflow WDT, 32kHz ACLK 
;
;    Description; Toggle P5.1 using software timed by WDT . Toggle rate is 
;   exactly 250ms based on 32kHz ACLK WDT clock source.  In this example the 
;   WDT is configured to divide 32768 watch-crystal(2^15) by 2^13 with an ISR 
;   triggered @ 4Hz.  
;   ACLK = LFXT1 = 32768, MCLK = SMCLK = DCO 
;   //*An external watch crystal on XIN XOUT is required for ACLK*//
;
;                 MSP430F449
;             -----------------
;         /|\|              XIN|-  
;          | |                 |
;          --|RST          XOUT|-
;            |                 |
;            |             P5.1|-->LED
;
;  Yang Rui
;  Lierda, Inc
;  NOVEMBER 2003
;  Built with IAR Embedded Workbench Version: 1.26B
;------------------------------------------------------------------------------ 
            ORG     01100h                  ; Program Start
;------------------------------------------------------------------------------ 
RESET       mov.w   #0a00h,SP               ; Initialize '449 stackpointer
SetupWDT    mov.w   #WDT_ARST_250,&WDTCTL    ; WDT ~250ms interval timer 
                                                             
            mov   #07fffh,R15
loop        dec   R15                                            					  
            jnz     loop
            
;------------------------------------------------------------------------------
;    Toggle P5.1
;------------------------------------------------------------------------------
            bis.b   #002h,&P5DIR            ; P5.1 output
            bis.b   #002h,&P5OUT            ; Toggle P5.1
      
              
                                                             
loop_1      mov   #07fffh,R15               ;wait for WDT reset 
            dec    R15                                            					  
            jnz     loop_1           
;----------------------------------------------------------------------------- 
;           Interrupt Vectors Used MSP430x44x          
;----------------------------------------------------------------------------- 
            ORG     0FFFEh                  ; MSP430 RESET Vector
            DW      RESET                   ; 
            
            END