5-inch-TFT-Touch-LCD +SD card

I am using Arduino Mega 2560 wired with touch screen with out any shield and its work, but SD card didn’t work fine
the connection is
53 sd cs
52 sd sck
51 sd D in
50 sd D o

also the test code

#include <SD.h>

File myFile;

void setup()
{
Serial.begin(9600);
Serial.print(“Initializing SD card…”);

pinMode(53, OUTPUT);

if (!SD.begin(53)) {
Serial.println(“initialization failed!”);
return;
}
Serial.println(“initialization done.”);

// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
myFile = SD.open(“test.txt”, FILE_WRITE);

// if the file opened okay, write to it:
if (myFile) {
Serial.print(“Writing to test.txt…”);
myFile.println(“testing 1, 2, 3.”);
// close the file:
myFile.close();
Serial.println(“done.”);
} else {
// if the file didn’t open, print an error:
Serial.println(“error opening test.txt”);
}
}

void loop()
{
// nothing happens after setup
}

please some help !