51单片机8255驱动C程序

/*---------------------------------------------------------------------------------------------------------------- 
库文件名称：driver8155.h 
功能描述：驱动8155，不需要了解8255的工作原理，透明操作8255的三个输入输出口PA、PB、PC 

读A口只需要调用rd_PA,写则需要调用wr_PA;B、C操作也一样

全局变量: IO_flags，在其它程序中不能对其改写 
特殊说明: 无 
//----------------------------------------------------------------------------------------------------------------*/ 
 #include 
unsigned char const cfg_table[8]={ 
             0x80,       /*10000000b,       ;c=out  b=out  a=out*/ 
             0x90,       /*10010000b,       ;c=out  b=out  a=in */ 
             0x82,       /*10000010b,       ;c=out  b=in   a=out*/ 
             0x92,       /*10010010b,       ;c=out  b=in   a=in */ 
             0x89,       /*10001001b,       ;c=in   b=out  a=out*/ 
             0x99,       /*10011001b,       ;c=in   b=out  a=in */ 
             0x8B,       /*10001011b,       ;c=in   b=in   a=out*/ 
             0x9B,       /*10011011b,       ;c=in   b=in   a=in */ 
             }; 
unsigned char rd_mem(unsigned char mem_ad) 
             { 
             } 

void PABC_config(void ) 
              { 
              a8255_CON=cfg_table[IO_flags]; 
              } 

char rd_PA(void)                         /*读PA口*/ 
                { 
               unsigned char PA_data; 
               ACC=IO_flags;             /*把状态标志字读到ACC便于进行位操作*/ 
               do 
               { 
                IO_flagsA=1;              /*置PA状态标志位为高--输入*/ 
                IO_flags=ACC; 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;                     
                } 
                while(IO_flagsA==0);     /*判断状态标志位是否为高*/ 
                                         /*控制字设置完成*/ 
                PA_data=a8255_PA;         /*把PA口的数据读到PA_data*/ 
                return(PA_data);         /*返回PA_data*/ 
                } 
char rd_PB(void)                         /*读PB口*/ 
                { 
               unsigned char PB_data; 
               ACC=IO_flags;             /*把状态标志字读到ACC便于进行位操作*/ 
               do 
               { 
                IO_flagsB=1;              /*置PB状态标志位为高--输入*/ 
                IO_flags=ACC; 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;                     
                } 
                while(IO_flagsB==0);     /*判断状态标志位是否为高*/ 
                                         /*控制字设置完成*/ 
                PB_data=a8255_PB;         /*把PA口的数据读到PB_data*/ 
                return(PB_data);         /*返回PB_data*/ 
                } 
char rd_PC(void)                         /*读PC口*/ 
                { 
               unsigned char PC_data; 
               ACC=IO_flags;             /*把状态标志字读到ACC便于进行位操作*/ 
               do 
               { 
                IO_flagsC=1;              /*置PC状态标志位为高--输入*/ 
                IO_flags=ACC; 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;                     
                } 
                while(IO_flagsC==0);     /*判断状态标志位是否为高*/ 
                                         /*控制字设置完成*/ 
                PC_data=a8255_PC;         /*把PC口的数据读到PC_data*/ 
                return(PC_data);         /*返回PC_data*/ 
                } 

void wd_PA(unsigned char PA_data)          /*写PA口*/ 
                { 
                ACC=IO_flags;              /*把状态标志字读到ACC便于进行位操作*/ 
              
                {IO_flagsA=0;              /*置PA状态标志位为低--输出*/ 
                IO_flags=ACC;              /*位操作完成，把ACC的内容写回状态标志字*/ 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;               
                } 
                while(IO_flagsA==1);      /*判断状态标志位是否为高 
                                            为高，设置未完成，需从新设置*/ 

               a8255_PA=PA_data;           /*将PA_data的内容送到PA口*/ 
                } 
void wd_PB(unsigned char PB_data)          /*写PB口*/ 
                { 
                ACC=IO_flags;              /*把状态标志字读到ACC便于进行位操作*/ 
              
                {IO_flagsB=0;              /*置PB状态标志位为低--输出*/ 
                IO_flags=ACC;              /*位操作完成，把ACC的内容写回状态标志字*/ 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;               
                } 
                while(IO_flagsB==1);      /*判断状态标志位是否为高 
                                            为高，设置未完成，需从新设置*/ 

               a8255_PB=PB_data;           /*将PB_data的内容送到PB口*/ 
                } 
void wd_PC(unsigned char PC_data)          /*写PC口*/ 
                { 
                ACC=IO_flags;              /*把状态标志字读到ACC便于进行位操作*/ 
              
                {IO_flagsC=0;              /*置PC状态标志位为低--输出*/ 
                IO_flags=ACC;              /*位操作完成，把ACC的内容写回状态标志字*/ 
                PABC_config();              /*调用配置子程序，完成对8255的设置*/ 
                ACC=IO_flags;               
                } 
                while(IO_flagsC==1);      /*判断状态标志位是否为高 
                                            为高，设置未完成，需从新设置*/ 

               a8255_PC=PC_data;           /*将PC_data的内容送到PC口*/ 
                } 
void set_PC(unsigned char PC_num) 
             { 
             ACC=IO_flags; 
             IO_flagsC=0; 
             ACC=IO_flags; 
             PC_num=PC_num<<1; 
             PC_num=(PC_num|0x01); 
             a8255_CON=PC_num; 
               } 
void clr_PC(unsigned char PC_num) 
             { 
             ACC=IO_flags; 
             IO_flagsC=1; 
             ACC=IO_flags; 
             PC_num=PC_num<<1; 
             PC_num=(PC_num&0xFE); 
             a8255_CON=PC_num; 
               } 
               
void main(void) 
               { 
               set_PC(0x01); 
               }

/*---------------------------------------------------
文件名称：Config.h
功能描述：端口定义和RAM配置
输入参数：无
输出参数：无
特殊说明：根据具体分配的地址，重新设定各值
//----------------------------------------------------------------------------------------------------------------*/
#include
#include  
#define a8255_PA    XBYTE[0x7F7C]     /*PA口地址*/
#define a8255_PB    XBYTE[0x7F7D]     /*PB口地址*/
#define a8255_PC    XBYTE[0x7F7E]     /*PC口地址*/
#define a8255_CON   XBYTE[0x7F7F]     /*控制字地址*/
unsigned char IO_flags;   /* 用于表示PA、PB、PC的当前输入输出状态
                            内容不能被其它程序改写，操作时ACC=IO_flags*/                         
sbit    IO_flagsA=ACC^0;  /*PA的当前输入输出状态
                           置位表示输入，复位表示输出*/
sbit    IO_flagsB=ACC^1;  /*PB的当前输入输出状态*/
sbit    IO_flagsC=ACC^2;  /*PC的当前输入输出状态*/

char rd_PA(void);          /*读PA口*/  
char rd_PB(void);          /*读PB口*/
char rd_PC(void);          /*读PC口*/
void wd_PA(unsigned char PA_data);  /*写PA口*/
void wd_PB(unsigned char PB_data);  /*写PA口*/
void wd_PC(unsigned char PC_data);  /*写PA口*/
void PABC_config(void );            /*写8255控制字*/