84 lines
2.2 KiB
Arduino
84 lines
2.2 KiB
Arduino
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/*
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* This sketch reads and prints the tail of all files
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* created by SdFatAppend.pde, SdFatPrint.pde, and
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* SdFatWrite.pde.
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*/
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#include <SdFat.h>
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#include <SdFatUtil.h> // use functions to print strings from flash memory
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const uint8_t SD_CHIP_SELECT = SS;
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SdFat sd;
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SdFile file;
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// store error strings in flash to save RAM
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#define error(s) sd.errorHalt_P(PSTR(s))
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void setup(void) {
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Serial.begin(9600);
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while (!Serial) {} // wait for Leonardo
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PgmPrintln("Type any character to start");
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while (Serial.read() <= 0) {}
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delay(200); // Catch Due reset problem
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// initialize the SD card at SPI_HALF_SPEED to avoid bus errors with
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// breadboards. use SPI_FULL_SPEED for better performance.
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if (!sd.begin(SD_CHIP_SELECT, SPI_HALF_SPEED)) sd.initErrorHalt();
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// start at beginning of root directory
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sd.vwd()->rewind();
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}
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/*
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* Print tail of all SdFat example files
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*/
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void loop(void) {
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dir_t dir;
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char name[13];
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// read next directory entry in current working directory
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if (sd.vwd()->readDir(&dir) != sizeof(dir)) {
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Serial.println("End of Directory");
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while(1);
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}
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// check for file name "APPEND.TXT", "PRINT*.TXT"
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// or "WRITE*.TXT"
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// first 8 bytes are blank filled name
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// last three bytes are blank filled extension
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if ((strncmp((char *)dir.name, "APPEND ", 8) &&
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strncmp((char *)dir.name, "PRINT", 5) &&
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strncmp((char *)dir.name, "WRITE", 5)) ||
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strncmp((char *)&dir.name[8], "TXT", 3)) {
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return;
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}
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// format file name
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SdFile::dirName(dir, name);
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// remember position in directory
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uint32_t pos = sd.vwd()->curPosition();
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// open file
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if (!file.open(name, O_READ)) error("file.open failed");
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// restore root position
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if (!sd.vwd()->seekSet(pos)) error("seekSet failed");
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// print file name message
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Serial.print("Tail of: ");
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Serial.println(name);
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// position to tail of file
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if (file.fileSize() > 100) {
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if (!file.seekSet(file.fileSize() - 100)) error("file.seekSet failed");
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}
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int16_t c;
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// find end of line
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while ((c = file.read()) > 0 && c != '\n');
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// print rest of file
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while ((c = file.read()) > 0) Serial.write((char)c);
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file.close();
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Serial.println();
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}
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