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81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
/*
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* This program demonstrates the freeClusterCount() call.
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*/
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#include <SPI.h>
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#include "SdFat.h"
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/*
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* SD chip select pin. Common values are:
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*
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* Arduino Ethernet shield, pin 4.
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* SparkFun SD shield, pin 8.
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* Adafruit Datalogging shield, pin 10.
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* Default SD chip select is the SPI SS pin.
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*/
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const uint8_t chipSelect = SS;
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#define TEST_FILE "Cluster.test"
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// file system
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SdFat sd;
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// test file
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SdFile file;
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// Serial output stream
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ArduinoOutStream cout(Serial);
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//------------------------------------------------------------------------------
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void printFreeSpace() {
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cout << F("freeClusterCount() call time: ");
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uint32_t m = micros();
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uint32_t volFree = sd.vol()->freeClusterCount();
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cout << micros() - m << F(" micros\n");
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cout << F("freeClusters: ") << volFree << setprecision(3) << endl;
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float fs = 0.000512*volFree*sd.vol()->blocksPerCluster();
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cout << F("freeSpace: ") << fs << F(" MB (MB = 1,000,000 bytes)\n\n");
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}
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//------------------------------------------------------------------------------
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void setup() {
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Serial.begin(9600);
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// Wait for USB Serial
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while (!Serial) {
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SysCall::yield();
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}
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if (!MAINTAIN_FREE_CLUSTER_COUNT) {
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cout << F("Please edit SdFatConfig.h and set\n");
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cout << F("MAINTAIN_FREE_CLUSTER_COUNT nonzero for\n");
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cout << F("maximum freeClusterCount() performance.\n\n");
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}
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// F stores strings in flash to save RAM
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cout << F("Type any character to start\n");
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while (!Serial.available()) {
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SysCall::yield();
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}
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// Initialize at the highest speed supported by the board that is
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// not over 50 MHz. Try a lower speed if SPI errors occur.
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if (!sd.begin(chipSelect, SD_SCK_MHZ(50))) {
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sd.initErrorHalt();
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}
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// Insure no TEST_FILE.
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sd.remove(TEST_FILE);
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cout << F("\nFirst call to freeClusterCount scans the FAT.\n\n");
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printFreeSpace();
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cout << F("Create and write to ") << TEST_FILE << endl;
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if (!file.open(TEST_FILE, O_WRITE | O_CREAT)) {
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sd.errorHalt(F("Create failed"));
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}
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file.print(F("Cause a cluster to be allocated"));
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file.close();
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cout << F("\nSecond freeClusterCount call is faster if\n");
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cout << F("MAINTAIN_FREE_CLUSTER_COUNT is nonzero.\n\n");
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printFreeSpace();
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cout << F("Remove ") << TEST_FILE << endl << endl;
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sd.remove(TEST_FILE);
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printFreeSpace();
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cout << F("Done") << endl;
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}
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//------------------------------------------------------------------------------
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void loop() {} |