Hardware Configuration SdFat was developed using an Adafruit Industries Wave Shield. They seem to have more internal RAM buffering than other cards and therefore can limit the number of flash erase operations that the Arduino forces due to its limited RAM. SanDisk cards generally have good write performance. The Arduino cannot optimize writes to reduce erase operations because of its limit RAM. Write performance is limited by how efficiently the card manages internal erase/remapping operations. Most cards have good SPI read performance but cards vary widely in SPI write performance. ![]() A card that functions well on A PC or Mac may not work well on the Arduino. PCs, Macs, and most consumer devices use the 4-bit parallel SD protocol. SD\SDHC Cards Arduinos access SD cards using the cards SPI protocol. These functions reduce write latency so that audio can be recorded with the small amount of RAM in the Arduino. This application uses special Sd2Card calls to write to contiguous files in raw mode. SdFat was used to implement an audio record/play class, WaveRP, for the Adafruit Wave Shield. SdFat was developed for high speed data recording. These were developed to test SdFat and illustrate its use. A number of example are provided in the SdFat/examples folder. This class supports access to the root directory and subdirectories. The SdFile class provides file access functions such as open(), read(), remove(), write(), close() and sync(). ![]() Most applications will only need to call the SdVolume::init() member function. The SdVolume class supports FAT16 and FAT32 partitions. Most applications will only need to call the Sd2Card::init() member function. The Sd2Card class supports access to standard SD cards and SDHC cards. The main classes in SdFat are Sd2Card, SdVolume, and SdFile. Standard SD and high capacity SDHC cards are supported. 1 Arduino SdFat Library Copyright (C) 2009 by William Greiman Introduction The Arduino SdFat Library is a minimal implementation of FAT16 and FAT32 file systems on SD flash memory cards.
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