;*******************************************************************************
;   MSP430F20x1 Demo - Comp_A, Output Reference Voltages on P1.1
;
;   Description: Output comparator_A reference levels on P1.1.  Program will
;   cycle through the on-chip comparator_A reference voltages with output on
;   P1.1. Normal mode is LPM0 with TA0 triggering interrupt for next mode.
;   ACLK = n/a, MCLK = SMCLK = default DCO
;
;		 MSP430F20x1
;             -----------------
;         /|\|              XIN|-
;          | |                 |
;          --|RST          XOUT|-
;            |                 |
;            |         CA1/P1.1|-->Vref
;            |                 |			
;
;   M. Buccini / L. Westlund
;   Texas Instruments Inc.
;   November 2005
;   Built with IAR Embedded Workbench Version: 3.40A
;*******************************************************************************
#include  "msp430x20x1.h"
;-------------------------------------------------------------------------------
            ORG     0F800h                  ; Program Reset
;-------------------------------------------------------------------------------
RESET       mov.w   #0280h,SP               ; Initialize stackpointer
StopWDT     mov.w   #WDTPW+WDTHOLD,&WDTCTL  ; Stop WDT
            mov.b   #P2CA4,&CACTL2          ; CA1
SetupC0     mov.w   #CCIE,&CCTL0            ; CCR0 interrupt enabled
SetupTA     mov.w   #TASSEL_2+ID_3+MC_2,&TACTL   ; SMCLK/8, contmode
            eint                            ; General enable interrupts
                                            ;
Mainloop    clr.b   &CACTL1                 ; No reference voltage
            bis.w   #CPUOFF,SR              ; CPU off
Ref1        mov.b   #CAREF0+CAON,&CACTL1    ; 0.25*Vcc, Comp. on
            bis.w   #CPUOFF,SR              ; CPU off
Ref2        mov.b   #CAREF1+CAON,&CACTL1    ; 0.5*Vcc, Comp. on
            bis.w   #CPUOFF,SR              ; CPU off
Ref3        mov.b   #CAREF1+CAREF0+CAON,&CACTL1     ; 0.55V on P2.3, Comp. on
            bis.w   #CPUOFF,SR              ; CPU off
            jmp     Mainloop                ;

;-------------------------------------------------------------------------------
TA0_ISR;    Exit LPM0
;-------------------------------------------------------------------------------
            bic.w   #CPUOFF,0(SP)           ; Exit LPM0 on RETI
            reti                            ;		
                                            ;
;-------------------------------------------------------------------------------
;           Interrupt Vectors
;-------------------------------------------------------------------------------
            ORG     0FFFEh                  ; MSP430 RESET Vector
            DW      RESET                   ;
            ORG     0FFF2h                  ; Timer_A0 Vector
            DW      TA0_ISR                 ;
            END