62256.c

使用OKI公司8255A控制62256RAM程序,并使用8803液晶显示

#define CS_ram          PORTA.7
#define CS_ram_en       DDRA.7
void writeram(unsigned int address,unsigned char data)
{unsigned char temp=0;
 CS_ram_en=1;
 CS_ram=1;
 temp=address;
 send_a(temp);
 address=address>>8;
 temp=address;
 send_b(temp);
 BUS_out=data;  
 
 CS_ram=0;//片选上62256   
 #asm("NOP")
 WR=0;
 WR=1;
 #asm("NOP")
 CS_ram=1; 
 }
unsigned char readram(unsigned int address)
{unsigned char temp=0;
 //CS_ram_en=1;
 CS_ram=1;
 temp=address;
 send_a(temp);
 address=address>>8;
 temp=address;
 send_b(temp);
 CS_ram=0;//片选上62256  
 BUS_en=0x00;
 BUS_out=0x00;
 RD=0; 
 #asm
 NOP
 NOP
 #endasm
 temp=BUS_in;
 RD=1; 
 CS_ram=1; 
 return temp; 
 }