The SPI port on mega is not the pin 10,11,12,13, so it can not control the sd card through these pins.
The SPI pin on mega is as follows:
CS->PB0
MISO->PB3
MOSI->PB2
CLK->PB1
The SPI port on mega is not the pin 10,11,12,13, so it can not control the sd card through these pins.
The SPI pin on mega is as follows:
CS->PB0
MISO->PB3
MOSI->PB2
CLK->PB1