HELP code giao tiếp pic với thẻ nhớ

[vanlamhaui]

em tìm dk cái code này trên mạng nhưng ko hiểu lắm bác nào biết gt hộ em với ạ.


#include <16F877.H>
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#use fast_io(C)
#byte SSPBUF = 0x13
#byte SSPCON = 0x14
#byte SSPSTAT = 0x94
#bit BF = SSPSTAT.0
#bit SMP = SSPSTAT.7
#bit CKE = SSPSTAT.6
#bit CKP = SSPCON.4
#bit SSPM1 = SSPCON.1
#bit SSPEN = SSPCON.5

#byte PORTC = 7
#bit CS = PORTC.2

//****************************************
// This is the same as the CCS spi_read() function.

char SPI(char d)
{
SSPBUF=d;
while (!BF);
return SSPBUF;
}

//******************************************

char Command(char befF, int16 AdrH, int16 AdrL, char befH)
{
SPI(0xFF);
SPI(befF);
SPI(AdrH >> 8);
SPI(AdrH);
SPI(AdrL >> 8);
SPI(AdrL);
SPI(befH);
SPI(0xFF);
return SPI(0xFF); // Return with the response
}
//********************************************

char MMC_Init()
{
char i;

// Init SPI
SMP=0;
CKE=0;
CKP=1;
SSPM1=1;
//SSPM0=1;
SSPEN=1;

CS=1; // MMC-Disabled

// MMC in SPI Mode -- start and Reset.
for(i=0; i < 10; i++) SPI(0xFF); // 10*8=80 clocks
CS=0; // MMC-Enabled

// CMD0
if (Command(0x40,0,0,0x95) !=1) goto Error; // Reset

st:
// CMD1
if (Command(0x41,0,0,0xFF) !=0) goto st ; // CMD1

return 1;

Error:
return 0;
}
//*********************************************

void main(void)
{
int16 i;
setup_port_a(NO_ANALOGS);
set_tris_c(0b11010011); // sck rc3-0, sdo rc5-0, CS rc2-0.
set_tris_b(0b00000010);
puts("Start\n\r");
if(MMC_Init())
puts("MMC ON\n\r"); // MMC Init OK

//*****************************************

// Write in 512 Byte-Mode
if (Command(0x58,0,512,0xFF) !=0) puts("Write error ");
SPI(0xFF);
SPI(0xFF);
SPI(0xFE);

SPI("Begin\n\r"); // 7 characters

for(i=0; i < 500; i++) // Was 512, but used 12 for text
{
SPI('M');
}
SPI("\n\rEnd"); // 5 characters


SPI(255); // Send two bytes of 0xFF at the end
SPI(255);
i=SPI(0xFF);
i &=0b00011111;
if (i != 0b00000101) puts("Write Error ");
while(SPI(0xFF) !=0xFF); // Wait for end of Busy condition

//*************************************

// Read in 512 Byte-Mode
if (Command(0x51,0,512,0xFF) !=0) puts("Read Error ");

while(SPI(0xFF) != 0xFE);

for(i=0; i < 512; i++)
{
putc(SPI(0xFF)); // Send data
}
SPI(0xFF); // Send two bytes of 0xFF at the end
SPI(0xFF);



//**********************************************
while(1); // The program stops here.
}

[_KUL_]

bác co sơ đồ nguyên lý không ạ cho em xin với

[thaongoc_]

Cái này giao tiếp với thẻ nhớ bằng SPI thui mà