实验7_比较器a.s43

msp430系列开发板源代码

#include  "msp430x44x.h"
;******************************************************************************
;   MSP-Test44x Demo - Comp_A Detect Theashold, Set P5.1 if P1.6 > 0.25*Vcc  
;
;   Description; Use comparator_A to detect a voltage threashold. Using an
;   external potentiometer, an interesting analog voltage is applied to P2.3. 
;   Comparator_A compares the interesting voltage to an internal reference 
;   voltage, in this example 0.25*VCC.  If the interesting voltage is higher 
;   than 0.25*Vcc, P5.1 is set, if not, P5.1 is reset.
;   ACLK = n/a, MCLK = SMCLK = default DCO ~ 800k 
;
;                 MSP430F449
;             -----------------
;        /|\ |              XIN|-  
;         |  |                 |
;         ---|RST          XOUT|-
;         |  |                 |
;         R<-|P1.6         P5.1|--> LED
;         |  |                 |			 
;         ---|VSS
;

;------------------------------------------------------------------------------ 
            ORG     01100h                  ; Program Start
;------------------------------------------------------------------------------ 
RESET       mov.w   #0A00h,SP               ; Initialize stackpointer
StopWDT     mov.w   #WDTPW+WDTHOLD,&WDTCTL  ; Stop WDT
SetupP1     bis.b   #002h,&P5DIR            ; P5.1 = output
SetupCA     mov.b   #CARSEL+CAREF0+CAON,&CACTL1   ; 0.25Vcc = -comp, on
            mov.b   #P2CA0,&CACTL2          ; P1.6 = +comp 
                                            ;													  
Mainloop    bit.b   #CAOUT,&CACTL2          ; Test comparator_A output
            jz      OFF                     ; jmp--> if CAOUT reset
                                            ;
ON          bis.b   #002h,&P5OUT            ; P5.1 = 1 
            jmp     Mainloop                ;  
OFF         bic.b   #002h,&P5OUT            ; P5.1 = 0 
            jmp     Mainloop                ;  
                                            ;
;------------------------------------------------------------------------------ 
;           Interrupt Vectors Used MSP430F449         
;------------------------------------------------------------------------------ 
            ORG     0FFFEh                  ; MSP430 RESET Vector
            DW      RESET                   ; 
            END