fet110_ta_23.s43

MSP430X110A demo 汇编语言程序。

;******************************************************************************
;   MSP-FET430x110 Demo - Timer_A, Ultra-Low Pwr 1200Hz Detect, ACLK +/- 5%
;
;   Description: Using Timer_A capture capability. At 250ms intervals,
;   CCR0 is enabled on P2.2 to detect presence or absence of 1200Hz. If
;   1200Hz is present, P1.0 is set, if not, reset. WDT is used for 250ms
;   wake-up to hunt for tone. System runs normally in LPM3.
;   //* External watch crystal installed on XIN XOUT is required for ACLK *//	
;
;        32768Hz = ACLK
;        1200Hz  = 27.3 ACLK clocks
;        1260Hz  = 26 ACLK clocks
;        1730Hz  = 28 ACLK clock
;
;                MSP430F1121
;             -----------------
;         /|\|              XIN|-
;          | |                 | 32kHz
;          --|RST          XOUT|-
;            |                 |
;    Signal->|P2.2/CCR0    P1.0|-->LED
;            |                 |			
;
;
;           CPU registers used
#define     Period  R15
#define     OldCap  R14
;
;   M. Buccini
;   Texas Instruments Inc.
;   Feb 2005
;   Built with IAR Embedded Workbench Version: 3.21A
;*****************************************************************************
#include  <msp430x11x1.h>
;------------------------------------------------------------------------------
            ORG     0F000h                  ; Program Start
;------------------------------------------------------------------------------
RESET       mov.w   #300h,SP		    ; Initialize stackpointer
SetupWDT    mov.w   #WDT_ADLY_250,&WDTCTL   ; WDT 250ms Interval Timer
            bis.b   #WDTIE,&IE1             ; Enable WDT Interrupt
SetupP1     mov.b   #0FFh,&P1DIR            ; All P1.x Outputs
            clr.b   &P1OUT                  ; All P1.x Reset
SetupP2     mov.b   #0FBh,&P2DIR            ; P2.2 Input / All P2.x Output
            bis.b   #004h,&P2SEL            ; P2.2 CCR0 input
            clr.b   &P2OUT                  ; All P2.x Reset
                                            ;
Mainloop    bis.w   #LPM3+GIE,SR            ; Enter LPM3 W/ interrupts
            call    #Get_CCR0               ; Capture CCR0 on P2.2
            cmp.w   #029,Period             ;
            jhs     OFF                     ;
            cmp.w   #026,Period             ;
            jlo     OFF                     ;
                                            ;
ON          bis.b   #001h,&P1OUT            ; P1.0 = 1
            jmp     Mainloop                ;
OFF         bic.b   #001h,&P1OUT            ; P1.0 = 0
            jmp     Mainloop                ;
                                            ;
;------------------------------------------------------------------------------
Get_CCR0; Subroutine to get CCR0 Capture
;------------------------------------------------------------------------------
            clr     Period                  ;
            clr     OldCap                  ;
            mov     #TASSEL0+TACLR,&TACTL   ; ACLK, TAR cleared
SetupC0     mov     #CCIS0+CM0+CAP+CCIE+SCS,&CCTL0  ; CCI0B, CAP, interrupt
            bis     #MC1,&TACTL             ; Start timer in continuous mode
Test_1      cmp     #0112,&TAR              ; Timeout
            jlo     Test_1                  ; jump if 112 > &TAR - timeout
            clr     &TACTL                  ; Stop Timer_A
            clr     &CCTL0                  ; Stop CCTL0
            ret                             ;
                                            ;
;------------------------------------------------------------------------------
TA0_ISR;    Timer_A C0 ISR
;------------------------------------------------------------------------------
            push.w  &CCR0                   ; Captured TAR, rising edge
            mov.w   @SP,Period              ;
            sub.w   OldCap,Period           ; New - old = period
            pop.w   OldCap                  ; For next calculation
            reti                            ;
                                            ;
;------------------------------------------------------------------------------
WDT_ISR;    Exit LPM3 on reti
;------------------------------------------------------------------------------
            bic.w    #LPM3,0(SP)            ; Clear LPM3 from TOS
            reti                            ;		
                                            ;
;------------------------------------------------------------------------------
;           Interrupt Vectors
;------------------------------------------------------------------------------
            ORG     0FFFEh                  ; MSP430 RESET Vector
            DW      RESET                   ;
            ORG     0FFF4h                  ; WDT Vector
            DW      WDT_ISR                 ;
            ORG     0FFF2h                  ; Timer_A0 Vector
            DW      TA0_ISR                 ;
            END