main.asm

来自「IIC MC9S12DG128 主机向从机写」· 汇编 代码 · 共 55 行

;**************************************************************
;* This stationery serves as the framework for a              *
;* user application. For a more comprehensive program that    *
;* demonstrates the more advanced functionality of this       *
;* processor, please see the demonstration applications       *
;* located in the examples subdirectory of the                *
;* Freescale CodeWarrior for the HC12 Program directory       *
;**************************************************************

; export symbols
            XDEF Entry, main
            ; we use export 'Entry' as symbol. This allows us to
            ; reference 'Entry' either in the linker .prm file
            ; or from C/C++ later on

            XREF __SEG_END_SSTACK      ; symbol defined by the linker for the end of the stack

; include derivative specific macros
            INCLUDE 'mc9s12dg128.inc'



; variable/data section
MY_EXTENDED_RAM: SECTION


; code section
MyCode:     SECTION
main:
Entry:


 LDS  #__SEG_END_SSTACK 
          
          SEI       
        
START:    MOVB  #$60,IBFD
          BSET  IBSR,#$10                
          BSET  IBAD,#$40
          BCLR  IBCR,#$30;从机模式，接收模式
          BSET  IBCR,#$80;使能IIC
          CLI
          
A_START:  
          BRSET IBSR,#$20,*  ;等待总线空闲
          BSET  IBCR,#$30    ;主机模式，发送模式
          BRCLR IBSR,#$20,*  ;总线忙
          MOVB  #$FE,IBDR    ;发送从机地址,(7位地址+0)
          BRCLR IBSR,#$80,*  ;等待传输完成
          BRCLR IBSR,#$02,*  ;总线忙
          BRSET IBSR,#$01,*  ;等待发送应答信号
          BSET  IBSR,#$02    ;中断标志位清零
   LOOP:
          JMP LOOP