MCS-51单片机应用子程序：11.8 12位串行DA转换器7543接口

START: MOV A,DBH ACALL ASMBB MOV SBUF,A MOV A,DBL ACALL ASMBB MOV SBUF,A MOV DPTR,#DAAD MOVX @DPTR,A RET ASMBB: MOV R6,#00H MOV R7,#08H CLR C ALO: RLC A XCH A,R6 RRC A XCH A,R6 DJNZ R7,ALO XCH A,R6 RET