fet140_spi0_0165.s43

TI低功耗MCU用例子

#include  "msp430x14x.h"
;******************************************************************************
;   MSP-FET430P140 Demo - USART0 SPI Interface to HC165 Shift Register 
;
;   Description: This program demonstrate a USART0 in SPI mode interface to a 
;   an 'HC165 shift register.  Read 8-bit Data from A-H are stored at a RAM
;   byte 0200h defined as Data.  
;   //**SWRST** please see MSP430x1xx Users Guide for description //
;
;                          MSP430F149
;                       -----------------
;                   /|\|              XIN|-  
;                    | |                 | 
;          HC165     --|RST          XOUT|-
;        ----------    |                 |
;    8  |      /LD|<---|P3.0             |    
;   -\->|A-H   CLK|<---|P3.3/UCLK0       |
;     |-|INH    QH|--->|P3.2/SOMI        |    
;     |-|SER      |    |                 | 
;     v
;
Data        equ     0200h                  
;
;   M.Buccini
;   Texas Instruments, Inc
;   January 2002
;******************************************************************************
;----------------------------------------------------------------------------- 
            ORG     01100h                  ; Program Start
;----------------------------------------------------------------------------- 
RESET       mov.w   #0A00h,SP               ; Initialize 'F149 stackpointer
            call    #Init_Sys               ; Initialize system
                                            ;
Mainloop    call    #RX_HC165               ; Read HC165
            mov.b   &RXBUF0,&Data           ; Data = HC165
            jmp     Mainloop                ; Repeat
                                            ;
;----------------------------------------------------------------------------- 
RX_HC165
;----------------------------------------------------------------------------- 
            bic.b   #01h,&P3OUT             ; Latch data into 'HC165
            bis.b   #01h,&P3OUT             ; 
            bic.b   #URXIFG0,&IFG1          ; Clear RXBUF flag
            mov.b   #00h,&TXBUF0            ; Dummy write to start SPI
L1          bit.b   #URXIFG0,&IFG1          ; RXBUF ready?
            jnc      L1                     ; 1 = ready
            ret                             ;
                                            ;
;----------------------------------------------------------------------------- 
Init_Sys;   Subroutine to Initialize MSP430F149 Peripherials
;----------------------------------------------------------------------------- 
StopWDT     mov.w   #WDTPW+WDTHOLD,&WDTCTL  ; Stop watchdog timer
SetupP3     bis.b   #0Ch,&P3SEL             ; P3.2,3 SPI option select
            bis.b   #09h,&P3DIR             ; P3.3,0 output direction
SetupSPI    bis.b   #040h,&ME1              ; Enable USART0 SPI
            bis.b   #CKPH+SSEL1+SSEL0+STC,&UTCTL0 ;* SMCLK, 3-pin mode
            mov.b   #CHAR+SYNC+MM,&UCTL0    ; 8-bit SPI Master **SWRST**
            mov.b   #02h,&UBR00             ; SMCLK/2 for baud rate
            clr.b   &UBR10                  ; SMCLK/2 for baud rate
            clr.b   &UMCTL0                 ; Clear modulation
            ret                             ; Return from subroutine
;
;-----------------------------------------------------------------------------
;           Interrupt Vectors Used MSP430x13x/14x         
;-----------------------------------------------------------------------------
             ORG     0FFFEh                  ; POR, ext. Reset, Watchdog, Flash
             DW      RESET                   ; 
             END