如何用SdFat从SD卡中删除最旧的文件

#include <SdFat.h>

const int SD_CHIP_SELECT_PIN = 10;

SdFat sd;
SdFile oldestFile;
uint32_t oldestTimestamp = UINT32_MAX;

void setup() {
  Serial.begin(9600);

  if (!sd.begin(SD_CHIP_SELECT_PIN)) {
    Serial.println("SD card initialization failed!");
    while (1);
  }

  if (!sd.chdir("/")) {
    Serial.println("Failed to open root directory!");
    while (1);
  }

  SdFile file;
  while (file.openNext(sd.vwd(), O_READ)) {
    if (!file.isDir()) {
      uint32_t timestamp = file.timestamp();
      if (timestamp < oldestTimestamp) {
        oldestTimestamp = timestamp;
        oldestFile = file;
      }
    }
    file.close();
  }

  if (!oldestFile.remove()) {
    Serial.println("Failed to delete the oldest file!");
    while (1);
  }

  Serial.println("Oldest file deleted successfully!");
}

void loop() {
  // 主循环代码
}