Some applications of microcontrollers like data loggers require a bulk of data storage and the internal EEPROM memory may not be sufficient. In such cases, use of SD memory card is a much cheaper solution.
This project demonstrates how to interface a SD card to ATmega8 microcontroller and transfer data (both in raw and FAT32 format) between the two. The data read from the SD card are transferred to a PC through RS232 connection and displayed on a Hyper-terminal window. Similarly, to write data to card, the data was fed through HyperTerminal, by typing some text.
For firmware and other details: SD/SDHC Card Interfacing with ATmega8