STC51單片機IO口模式快速設置

1、STC51單片機IO 口模式的快速設置新型51單片機STC(列,較傳統51單片機在性能和速度上有根 本性的提升.速度提升812倍；片上RAM大量增加；片上外圍模 塊大量增加,等等.其中IO 口的模式增加為4種(傳統51只有1中),以P0 口為例:這里,每個端口新增兩個存放器 PxM0, PxM1(x=0,1,2,3)在設置每一 個IO端的模式時都需要對這兩個存放器進行操作.比方：要將P0.7設為推挽輸出,P0.6設為準雙向口,P0.5設為高阻輸入；P0.4設為開路模式,P0.3-P0.0都設為準雙向口,那么需要如下的代碼：IO_Init()(P0M0=0x30;/0011 0000P0M1=0

2、x90;/1001 0000)這樣的設置不便于記憶,很容易寫錯,且寫好的代碼可讀性差,為此,我們可以通過一個宏定義來解決,具體如下：# define PORT00# define PORT11# define PORT22# define PORT33# define BIT00# define BIT11# define BIT22# define BIT33# define BIT44# define BIT55# define BIT66# define BIT77# define STANDARD 0# define PP_OUT1# define Z_IN2# define OD3

3、#define IOMODE(Port,bit_n,mode) switch(mode) case STANDARD: P0M0&=(1<<bit_n); P0M1&=(1<<bit_n); break;case PP_OUT: P0M0&=(1<<bit_n); P0M1|= (1<<bit_n); break;case Z_IN:P0M0|=(1<<bit_n); P0M1&=(1<<bit_n); break;case OD:P0M0|=(1<<bit_n); P0M1|=

4、(1<<bit_n); break;)一一switch(mode) case STANDARD: P1M0&=(1<<bit_n); P1M1&=(1<<bit_n); break;case PP_OUT: P1M0&=(1<<bit_n); P1M1|= (1<<bit_n); break;case Z_IN:P1M0|=(1<<bit_n); P1M1&=(1<<bit_n); break;case OD:P1M0|=(1<<bit_n);P1M1|=(1<

5、<bit_n); break;)一一switch(mode) case STANDARD: P2M0&=(1<<bit_n); P2M1&=(1<<bit_n); break;case PP_OUT: P2M0&=(1<<bit_n); P2M1|= (1<<bit_n); break;case Z_IN:P2M0|=(1<<bit_n); P2M1&=(1<<bit_n); break;case OD:P2M0|=(1<<bit_n); P2M1|=(1<<b

6、it_n); break;switch(mode) case STANDARD: P3M0&=(1<<bit_n); P3M1&=(1<<bit_n); break;case PP_OUT: P3M0&=(1<<bit_n); P3M1|= (1<<bit_n); break;case Z_IN:P3M0|=(1<<bit_n); P3M1&=(1<<bit_n); break;case OD:P3M0|=(1<<bit_n); P3M1|=(1<<bit_n); break;有了上面的宏定義,在初始化程序中可以直接這樣寫IO_Init()IOMODE(PORT0,BIT7,PP_OUT)IOMODE(PORT0,BIT6, STANDARD)IOMODE(PORT0,BIT5, Z_IN)IOMODE(PORT0,BIT4, OD)IOMODE(POR