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diff --git a/libraries/Robot_Control/Fat16mainpage.h b/libraries/Robot_Control/Fat16mainpage.h new file mode 100644 index 0000000..2c4f773 --- /dev/null +++ b/libraries/Robot_Control/Fat16mainpage.h @@ -0,0 +1,208 @@ +/* Arduino FAT16 Library + * Copyright (C) 2008 by William Greiman + * + * This file is part of the Arduino FAT16 Library + * + * This Library is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This Library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + + * You should have received a copy of the GNU General Public License + * along with the Arduino Fat16 Library. If not, see + * <http://www.gnu.org/licenses/>. + */ + +/** +\mainpage Arduino Fat16 Library +<CENTER>Copyright © 2008 by William Greiman +</CENTER> + +\section Intro Introduction +The Arduino Fat16 Library is a minimal implementation of the FAT16 file system +on standard SD flash memory cards. Fat16 supports read, write, file +creation, deletion, and truncation. + +The Fat16 class only supports access to files in the root directory and only +supports short 8.3 names. Directory time and date fields for creation +and modification can be maintained by providing a date/time callback +function \link Fat16::dateTimeCallback() dateTimeCallback()\endlink +or calling \link Fat16::timestamp() timestamp()\endlink. + +Fat16 was designed to use the Arduino Print class which +allows files to be written with \link Print::print() print() \endlink and +\link Print::println() println()\endlink. + +\section comment Bugs and Comments + +If you wish to report bugs or have comments, send email to fat16lib@sbcglobal.net. + + +\section SDcard SD Cards + +Arduinos access SD cards using the cards SPI protocol. PCs, Macs, and +most consumer devices use the 4-bit parallel SD protocol. A card that +functions well on A PC or Mac may not work well on the Arduino. + +Most cards have good SPI read performance but cards vary widely in SPI +write performance. Write performance is limited by how efficiently the +card manages internal erase/remapping operations. The Arduino cannot +optimize writes to reduce erase operations because of its limit RAM. + +SanDisk cards generally have good write performance. 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. + +Some Dane-Elec cards have a write speed that is only 20% as fast as +a good SanDisk card. + + +\section Hardware Hardware Configuration +Fat16 was developed using an <A HREF = "http://www.adafruit.com/"> Adafruit Industries</A> +<A HREF = "http://ladyada.net/make/gpsshield/modules.html"> GPS Shield</A>. + +The hardware interface to the SD card should not use a resistor based level +shifter. SdCard::init() sets the SPI bus frequency to 8 MHz which results in +signal rise times that are too slow for the edge detectors in many newer SD card +controllers when resistor voltage dividers are used. + +The 5 to 3.3 V level shifter for 5 V arduinos should be IC based like the +74HC4050N based circuit shown in the file SdLevel.png. The Adafruit Wave Shield +uses a 74AHC125N. Gravitech sells SD and MicroSD Card Adapters based on the +74LCX245. + +If you are using a resistor based level shifter and are having problems try +setting the SPI bus frequency to 4 MHz. This can be done by using +card.init(true) to initialize the SD card. + + +\section Fat16Class Fat16 Usage + +The class Fat16 is a minimal implementation of FAT16 on standard SD cards. +High Capacity SD cards, SDHC, are not supported. It should work on all +standard cards from 8MB to 2GB formatted with a FAT16 file system. + +\note + The Arduino Print class uses character +at a time writes so it was necessary to use a \link Fat16::sync() sync() \endlink +function to control when data is written to the SD card. + +\par +An application which writes to a file using \link Print::print() print()\endlink, +\link Print::println() println() \endlink +or \link Fat16::write write() \endlink must call \link Fat16::sync() sync() \endlink +at the appropriate time to force data and directory information to be written +to the SD Card. Data and directory information are also written to the SD card +when \link Fat16::close() close() \endlink is called. + +\par +Applications must use care calling \link Fat16::sync() sync() \endlink +since 2048 bytes of I/O is required to update file and +directory information. This includes writing the current data block, reading +the block that contains the directory entry for update, writing the directory +block back and reading back the current data block. + +Fat16 only supports access to files in the root directory and only supports +short 8.3 names. + +It is possible to open a file with two or more instances of Fat16. A file may +be corrupted if data is written to the file by more than one instance of Fat16. + +Short names are limited to 8 characters followed by an optional period (.) +and extension of up to 3 characters. The characters may be any combination +of letters and digits. The following special characters are also allowed: + +$ % ' - _ @ ~ ` ! ( ) { } ^ # & + +Short names are always converted to upper case and their original case +value is lost. + +Fat16 uses a slightly restricted form of short names. +Only printable ASCII characters are supported. No characters with code point +values greater than 127 are allowed. Space is not allowed even though space +was allowed in the API of early versions of DOS. + +Fat16 has been optimized for The Arduino ATmega168. Minimizing RAM use is the +highest priority goal followed by flash use and finally performance. +Most SD cards only support 512 byte block write operations so a 512 byte +cache buffer is used by Fat16. This is the main use of RAM. A small +amount of RAM is used to store key volume and file information. +Flash memory usage can be controlled by selecting options in Fat16Config.h. + +\section HowTo How to format SD Cards as FAT16 Volumes + +Microsoft operating systems support removable media formatted with a +Master Boot Record, MBR, or formatted as a super floppy with a FAT Boot Sector +in block zero. + +Microsoft operating systems expect MBR formatted removable media +to have only one partition. The first partition should be used. + +Microsoft operating systems do not support partitioning SD flash cards. +If you erase an SD card with a program like KillDisk, Most versions of +Windows will format the card as a super floppy. + +The best way to restore an SD card's MBR is to use SDFormatter +which can be downloaded from: + +http://www.sdcard.org/consumers/formatter/ + +SDFormatter does not have an option for FAT type so it may format +small cards as FAT12. + +After the MBR is restored by SDFormatter you may need to reformat small +cards that have been formatted FAT12 to force the volume type to be FAT16. + +The FAT type, FAT12, FAT16, or FAT32, is determined by the count +of clusters on the volume and nothing else. + +Microsoft published the following code for determining FAT type: + +\code +if (CountOfClusters < 4085) { + // Volume is FAT12 +} +else if (CountOfClusters < 65525) { + // Volume is FAT16 +} +else { + // Volume is FAT32 +} + +\endcode +If you format a FAT volume with an OS utility , choose a cluster size that +will result in: + +4084 < CountOfClusters && CountOfClusters < 65525 + +The volume will then be FAT16. + +If you are formatting an SD card on OS X or Linux, be sure to use the first +partition. Format this partition with a cluster count in above range. + +\section References References + +The Arduino site: + +http://www.arduino.cc/ + +For more information about FAT file systems see: + +http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx + +For information about using SD cards as SPI devices see: + +http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf + +The ATmega328 datasheet: + +http://www.atmel.com/dyn/resources/prod_documents/doc8161.pdf + + + */
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