iodemonichengxu.txt

i/o口对spi的模拟程序

#define      set_csn    (p1 |=1<<0)
#define      set_sck    (p1 |=1<<1)
#define      set_mosi    (p1 |=1<<2)
#define      set_miso    (p1 |=1<<3)
#define      clr_csn    (p1 &=~(1<<0))
#define      clr_sck    (p1 &=~(1<<1))
#define      clr_mosi    (p1 &=~(1<<2))
#define      clr_miso    (p1 &=~(1<<3))
void delay_us(unsigned int i)     /*i=2*/
{ while(i--)
NOP();
}
void delay_ms(unsigned int i)
{while(i--)
delay_us(1000);
}


//-------发送 一个字节-----
void  spi_RD(unsigned char data)
{unsigned char i;
clr_csn;
delay_ms(1);
for(i=0;i<8;i++)
  { clr_miso;
  if(data&0x01)
   set_miso;
   set_sck;
   delay_us(5);
   clr_sck;
  data>>1;
  }
clr_csn;
delay_ms(4);

}