fet140_adc12_05.asm

MSP430FX13x Assembler Examples Code,Composer Essentials Code Examples

;******************************************************************************
;   MSP-FET430P140 Demo - ADC12, Using an External Reference
;
;   Description: This program will show how to use an external positive
;                reference for the ADC12.
;
;   This example shows how to use an external positive reference for the ADC12.
;   The external reference is applied to the VeREF+ pin. Avss is used for the
;   negative reference. A single conversion is performed on channel A0. The
;   conversion results are stored in ADC12MEM0 and are moved to R5 after the
;   conversion is complete. Test by applying a voltage to channel A0, then
;   setting and running to a break point at "jmp Mainloop". To view the
;   conversion results, open a register window in debugger and view the contents
;   of R5.
;
;
;                  MSP430F149
;                ---------------
;               |               |
;        Vin -->|P6.0/A0        |
;               |               |
;        REF -->|VeREF+         |
;               |               |
;
;
;   M. Mitchell / G. Morton
;   Texas Instruments Inc.
;   May 2005
;   Built with Code Composer Essentials Version: 1.0
;******************************************************************************
 .cdecls C,LIST,  "msp430x14x.h"
;------------------------------------------------------------------------------
            .text                           ; Program Start
;------------------------------------------------------------------------------
RESET       mov     #0A00h,SP               ; Initialize stackpointer
StopWDT     mov     #WDTPW+WDTHOLD,&WDTCTL  ; Stop watchdog
            bis.b   #BIT0,&P6SEL            ; Enable A/D channel A0
                                            ;
SetupADC12  mov     #ADC12ON+SHT0_2,&ADC12CTL0  ; turn on ADC12, .set samp time
            mov     #SHP,&ADC12CTL1         ; Use sampling timer
            mov.b   #SREF_2,&ADC12MCTL0     ; Vr+=VeREF+ (external)
            bis     #ENC,&ADC12CTL0         ; Enable conversions
                                            ;
Mainloop    bis     #ADC12SC,&ADC12CTL0     ; Start conversions
testIFG     bit     #BIT0,&ADC12IFG         ; Conversion done?
            jz      testIFG                 ; No, test again
            mov     &ADC12MEM0, R5          ; Move result
            jmp     Mainloop                ; SET BREAKPOINT HERE
                                            ;
;------------------------------------------------------------------------------
;           Interrupt Vectors
;------------------------------------------------------------------------------
            .sect   ".reset"                ; MSP430 RESET Vector
            .short  RESET                   ;
            .end