8255.c

使用OKI公司8255A控制62256RAM程序,并使用8803液晶显示

#define WR      PORTB.0
#define WR_en   DDRB.0
#define RD      PORTB.1
#define RD_en   DDRB.1
#define CS      PORTB.4
#define CS_en   DDRB.4
#define A1      PORTB.5
#define A1_en   DDRB.5
#define A0      PORTB.6
#define A0_en   DDRB.6 
#define BUS_out PORTC
#define BUS_in  PINC
#define BUS_en  DDRC
void rest8255(unsigned char state)
{BUS_en=0xff;A1_en=1;A0_en=1;CS_en=1;RD_en=1;WR_en=1;
 BUS_out=0xff;
 CS=0;          //片选上
 A1=1;          A0=1;//写入寄存器
 WR=0;
 BUS_out=state;
 WR=1;
 CS=1;
 }
void send8255(unsigned char data,unsigned char direct) 
{BUS_en=0xff;
 CS=0;
 switch(direct)
 {case 0: A1=0;A0=0;break;
  case 1: A1=0;A0=1;break;
  case 2: A1=1;A0=0;break;
  case 3: A1=1;A0=1;break;
  } 
 WR=0;
 BUS_out=data;
 WR=1;
 CS=1;  
 }
void send_a(unsigned char data)
{BUS_en=0xff;
 CS=0;
 A1=0;A0=0; 
 WR=0;
 BUS_out=data;
 WR=1;
 CS=1;
 }
void send_b(unsigned char data)
{BUS_en=0xff;
 CS=0;
 A1=0;A0=1; 
 WR=0;
 BUS_out=data;
 WR=1;
 CS=1;
 } 
void send_c(unsigned char data)
{BUS_en=0xff;
 CS=0;
 A1=1;A0=0; 
 WR=0;
 BUS_out=data;
 WR=1;
 CS=1;
 }  
void send_r(unsigned char data)
{BUS_en=0xff;
 CS=0;
 A1=1;A0=1; 
 WR=0;
 BUS_out=data;
 WR=1;
 CS=1;
 }