Switch off the mode (command 'c') and change display units toĭisk /dev/mmcblk0: 3965 MB, 3965190144 bytesĤ9 heads, 48 sectors/track, 3292 cylinders WARNING: DOS-compatible mode is deprecated. I ran the following tests on the formatted card moved to the computer.to analyse the file system, hope it sudo fdisk /dev/mmcblk0

Warning, all data on the card will erased.į - erase and then format the card. This sketch can erase and/or format SD/SDHC cards.Įrase uses the card's fast flash erase command.įlash erase sets all data to 0X00 for most cardsĬards larger than 2 GB will be formatted FAT32 and If (!card.init(SPI_HALF_SPEED, 4)) sdError('card.init failed') To change chip select to pin 4 replace line 439 if (!card.init()) sdError('card.init failed') This will be a menu option in the future. This version has the chip select pin hard coded as the SPI SS pin. It chooses the best file system, FAT16/FAT32, the optimum cluster size, and aligns file system structures on the card's flash erase boundaries. For smaller cards, 16 - 64 MB, it use FAT16 instead of FAT12. PC/Mac/Linux format utilities do not comply with the above standard and do not produce optimal file system structures for the Arduino.įor SD/SDHC cards larger than 64 MB this sketch attempts to match the format generated by the formatter. It only runs on PCs and formats small SD cards as FAT12. I decided to write SdFormatter.pde since the only program I know that complies with the SD File System Specification is here: It is included as one of the examples, SdFormatter.pde, in the 20110414 beta of SdFat:

I finally decided to write a sketch to format SD cards. For three years I have been trying to find an easy way to correctly format SD cards for optimal use on the Arduino.

How to format sd card fat32