51單片機的位地址和字節地址

/*-*/;program name:  r8051xC2 -->Port0 Test Input or  Output;program versions: v1;program date: 2013.7.15;use : test;compiler: eng-12/*--*/$NOMOD51                //取消使用51內部默認SFR#include "REG8F301.INC"Key1        equ        P0.0F_1SSet        bit        20h.0F_KeyOne    bit        20h.1F_KeyOpen    bit        20h.2dseg    at      30h          //通用RAM字節段從30H開(kāi)始TimerCnt:    ds            1TimerCnt1:    ds            1KeyBuf:        ds            1KeyValue:    ds            1  P0_1:        ds            1P0_2:        ds            1P0_3:        ds            1P0_4:        ds            1P0_5:        ds            1P0_6:        ds            1P0_7:        ds            1P0_8:        ds            1IO_ModeCnt:    ds            1DelCnt:        ds            1iseg    at      80h     //0-ffh地址的RAM段     80h-ffh段RAM只能用間接尋址進(jìn)行操作cseg    at      0org            0hjmp            Startorg            0030h;start:                        mov            ckcon,#01hmov            r0,#0x7fClrRam:                              //清內部256Byte RAMmov            @r0,#0djnz        r0,ClrRam    mov            dptr,#0x00      //清外部768Byte RAM//    mov            dph,#0x03//    mov            dpl,#0x00ClrOutRam:mov            a,#0x00         //給外部RAM全部寫(xiě)0x00movx        @dptr,ainc            dplmov            a,dplcjne        a,#0,ClrOutRaminc            dphmov            a,dphcjne        a,#3,ClrOutRammov            P0_OE,#0ffh                    //設置P0位輸出模式mov            P0,#00H                        //P0輸出0;-main:mov            a,P0                        //IO口狀態(tài)快速翻轉，翻轉正常，在時(shí)鐘25Mhz下CPL            amov            P0,aljmp            main;-end