fet440_hfxt2.s43

MSP430 code examples

;******************************************************************************
;   MSP-FET430P440 Demo - FLL+, MCLK Configured to Operate from XT2 HF XTAL
;
;   Description: Proper selection of an external HF XTAL for MCLK is
;   demonstrated using HF XT2 OSC. OFIFG is polled until the HF XTAL
;   is stable - only then is MCLK sourced by XT2. MCLK is buffered on P1.4.
;   //** HF XTAL NOT INSTALLED ON FET **//
;
;                 MSP430F449
;             -----------------
;         /|\|              XIN|-
;          | |                 |
;          --|RST          XOUT|-
;            |                 |
;            |            XT2IN|-
;            |                 | HF XTAL (455kHz - 8MHz)
;            |           XT2OUT|-
;            |                 |
;            |        P1.1/MCLK|-->MCLK = HF XTAL
;
;   M. Buccini
;   Texas Instruments Inc.
;   Feb 2005
;   Built with IAR Embedded Workbench Version: 3.21A
;******************************************************************************
#include  <msp430x44x.h>
;------------------------------------------------------------------------------
            ORG     01100h                  ; Program Start
;------------------------------------------------------------------------------
RESET       mov.w   #0A00h,SP               ; Initialize stackpointer
StopWDT     mov.w   #WDTPW+WDTHOLD,&WDTCTL  ; Stop WDT
SetupP1     bis.b   #002h,&P1DIR            ; P1.1 output direction
            bis.b   #002h,&P1SEL            ; P1.1 option select
                                            ;
SetupHF     bic.b   #XT2OFF,&FLL_CTL1       ; Clear bit = high freq xtal on
ClearFlag   bic.b   #OFIFG,&IFG1            ; Clear osc fault flag
            mov     #0F000h,R15             ; Move delay time to register 15
HF_Wait     dec     R15                     ; Delay for xtal to start, FLL lock
            jnz     HF_Wait		    ; Loop if delay not finished
            bit.b   #OFIFG,&IFG1            ; Test osc fault flag
            jnz     ClearFlag               ; If not loop again
                                            ;
            bis.b   #SELM1,&FLL_CTL1        ; MCLK = XT2
                                            ;
Mainloop    jmp     Mainloop                ;
                                            ;
;-----------------------------------------------------------------------------
;           Interrupt Vectors
;-----------------------------------------------------------------------------
            ORG     0FFFEh                  ; RESET Vector
            DW      RESET                   ;
            END