來源：侃單片機 作者：etiller
修改：limiji
/*正常操作電壓為2.7~3.6V,實驗中發(fā)現(xiàn)當(dāng)電壓超過4.25V后讀出的狀態(tài)字節(jié)為9A（正常 */
/*的狀態(tài)字節(jié)值為9D）,并且讀寫數(shù)據(jù)均不準(zhǔn)確,所以應(yīng)當(dāng)保證卡片的供電電壓不超過 */
/*4.25V。 */
/*SPI規(guī)范：Data is always clocked into the device on the rising edge of SCK a-*/
/* nd clocked out of the device on the falling edge of SCK.All instruction-*/
/* s,addresses and data are transferred with the most significant bit(MSB) */
/* first. */
/* 2005-06-02*/
#define UCHAR unsigned char
#define UINT unsigned int
sbit SPI_CS = P2^2;
sbit SPI_SCK = P2^4;
sbit SPI_SO = P2^6;
sbit SPI_SI = P2^5;
sbit SPI_RESET = P2^3;
sbit SPI_WP = P2^1;
unsigned char SPI_HostReadByte(void){
unsigned char i,rByte=0;
for(i=0;i<8;i++){
SPI_SCK=0;
SPI_SCK=1;
rByte<<=1;
rByte =SPI_SO;
}
return rByte;
}
void SPI_HostWriteByte(unsigned char wByte){
unsigned char i;
for(i=0;i<8;i++){
if((wByte<<i)&0x80) {SPI_SI=1;}
else {SPI_SI=0;}
SPI_SCK=0;
SPI_SCK=1;
}
}
/*Status Register Format: */
/* ----------------------------------------------------------------------- */
/* bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 */
/* -------- -------- -------- -------- -------- -------- -------- -------- */
/* RDY/BUSY COMP 0 1 1 1 X X */
/* ----------------------------------------------------------------------- */
/* bit7 - 忙標(biāo)記,0為忙1為不忙。 */ |
66821730(技術(shù)支持)
