diff --git a/sdcard_task.cpp b/sdcard_task.cpp
new file mode 100644
index 0000000..d0a07e6
--- /dev/null
+++ b/sdcard_task.cpp
@@ -0,0 +1,198 @@
+#include "sdcard_task.h"
+#include "serial_task.h"
+#include <time.h>
+
+static SPIClass hspi(HSPI);
+volatile bool sdLoggingActive = false;
+char currentLogFileName[64] = "";
+static File logFile;
+static bool sdReady = false;
+static SemaphoreHandle_t sdMutex = NULL;
+
+void sdTaskInit() {
+  sdMutex = xSemaphoreCreateMutex();
+
+  hspi.begin(SD_HSPI_CLK, SD_HSPI_MISO, SD_HSPI_MOSI, SD_HSPI_CS);
+
+  if (!SD.begin(SD_HSPI_CS, hspi, 4000000)) {
+    Serial.println("[SD] Card mount FAILED!");
+    sdReady = false;
+  } else {
+    uint8_t cardType = SD.cardType();
+    if (cardType == CARD_NONE) {
+      Serial.println("[SD] No card detected!");
+      sdReady = false;
+    } else {
+      sdReady = true;
+      uint64_t cardSize = SD.cardSize() / (1024 * 1024);
+      Serial.printf("[SD] Card mounted. Type: %d, Size: %lluMB\n", cardType, cardSize);
+      hspi.setFrequency(20000000);
+
+      if (!SD.exists(LOG_DIR)) {
+        SD.mkdir(LOG_DIR);
+        Serial.println("[SD] Created /logs directory");
+      }
+      sdCreateNewLogFile();
+      sdLoggingActive = true;
+    }
+  }
+
+  xTaskCreatePinnedToCore(sdLoggingTask, "SDLog", TASK_STACK_SD_LOG,
+    NULL, TASK_PRIORITY_SD_LOG, NULL, 0);
+}
+
+bool sdCreateNewLogFile() {
+  if (!sdReady) return false;
+  xSemaphoreTake(sdMutex, portMAX_DELAY);
+
+  if (logFile) { logFile.flush(); logFile.close(); }
+
+  struct tm timeinfo;
+  time_t now;
+  time(&now);
+  localtime_r(&now, &timeinfo);
+
+  snprintf(currentLogFileName, sizeof(currentLogFileName),
+    "%s/LOG_%04d%02d%02d_%02d%02d%02d.csv",
+    LOG_DIR,
+    timeinfo.tm_year + 1900, timeinfo.tm_mon + 1, timeinfo.tm_mday,
+    timeinfo.tm_hour, timeinfo.tm_min, timeinfo.tm_sec);
+
+  logFile = SD.open(currentLogFileName, FILE_WRITE);
+  if (!logFile) {
+    Serial.printf("[SD] Failed to create: %s\n", currentLogFileName);
+    xSemaphoreGive(sdMutex);
+    return false;
+  }
+  logFile.print(CSV_HEADER);
+  logFile.flush();
+  Serial.printf("[SD] New log file: %s\n", currentLogFileName);
+  xSemaphoreGive(sdMutex);
+  return true;
+}
+
+void sdLoggingTask(void *param) {
+  Serial.println("[Task] SDLog started on core " + String(xPortGetCoreID()));
+
+  TickType_t lastFlush = xTaskGetTickCount();
+  int pendingWrites = 0;
+  char csvLine[LOG_LINE_MAX_LEN + 64];
+
+  while (true) {
+    LogEntry *entry;
+    if (xQueueReceive(queueSD, &entry, pdMS_TO_TICKS(100)) == pdTRUE) {
+      if (sdLoggingActive && sdReady && logFile) {
+        xSemaphoreTake(sdMutex, portMAX_DELAY);
+
+        int len = snprintf(csvLine, sizeof(csvLine),
+          "\"%s\",\"%c\",\"", entry->timestamp,
+          entry->direction == 'T' ? 'T' : 'R');
+
+        for (int i = 0; i < entry->dataLen && len < (int)sizeof(csvLine) - 4; i++) {
+          char c = entry->data[i];
+          if (c == '"') { csvLine[len++] = '"'; csvLine[len++] = '"'; }
+          else if (c >= 0x20 && c < 0x7F) { csvLine[len++] = c; }
+          else { len += snprintf(csvLine + len, sizeof(csvLine) - len, "\\x%02X", (uint8_t)c); }
+        }
+        len += snprintf(csvLine + len, sizeof(csvLine) - len, "\"\r\n");
+        logFile.write((uint8_t*)csvLine, len);
+        pendingWrites++;
+
+        xSemaphoreGive(sdMutex);
+      }
+      vPortFree(entry);
+    }
+
+    if (pendingWrites > 0 &&
+        (xTaskGetTickCount() - lastFlush) > pdMS_TO_TICKS(SD_WRITE_INTERVAL)) {
+      if (logFile) {
+        xSemaphoreTake(sdMutex, portMAX_DELAY);
+        logFile.flush();
+        xSemaphoreGive(sdMutex);
+      }
+      pendingWrites = 0;
+      lastFlush = xTaskGetTickCount();
+    }
+
+    if (pendingWrites >= 50) {
+      if (logFile) {
+        xSemaphoreTake(sdMutex, portMAX_DELAY);
+        logFile.flush();
+        xSemaphoreGive(sdMutex);
+      }
+      pendingWrites = 0;
+      lastFlush = xTaskGetTickCount();
+    }
+  }
+}
+
+void sdStopLogging() {
+  sdLoggingActive = false;
+  if (logFile) {
+    xSemaphoreTake(sdMutex, portMAX_DELAY);
+    logFile.flush();
+    logFile.close();
+    xSemaphoreGive(sdMutex);
+  }
+  Serial.println("[SD] Logging stopped");
+}
+
+void sdStartLogging() {
+  if (!sdReady) { Serial.println("[SD] Card not ready!"); return; }
+  if (!logFile || !sdLoggingActive) sdCreateNewLogFile();
+  sdLoggingActive = true;
+  Serial.println("[SD] Logging started");
+}
+
+String sdGetFileList() {
+  if (!sdReady) return "{\"files\":[]}";
+  xSemaphoreTake(sdMutex, portMAX_DELAY);
+
+  String json = "{\"files\":[";
+  File dir = SD.open(LOG_DIR);
+  bool first = true;
+
+  if (dir && dir.isDirectory()) {
+    File file = dir.openNextFile();
+    while (file) {
+      if (!file.isDirectory()) {
+        if (!first) json += ",";
+        first = false;
+        json += "{\"name\":\"";
+        json += file.name();
+        json += "\",\"size\":";
+        json += String(file.size());
+        time_t t = file.getLastWrite();
+        struct tm *tm = localtime(&t);
+        char timeBuf[32];
+        strftime(timeBuf, sizeof(timeBuf), "%Y-%m-%d %H:%M:%S", tm);
+        json += ",\"modified\":\"";
+        json += timeBuf;
+        json += "\"}";
+      }
+      file = dir.openNextFile();
+    }
+    dir.close();
+  }
+  json += "]}";
+  xSemaphoreGive(sdMutex);
+  return json;
+}
+
+bool sdDeleteFile(const char *filename) {
+  if (!sdReady) return false;
+  xSemaphoreTake(sdMutex, portMAX_DELAY);
+
+  char path[128];
+  snprintf(path, sizeof(path), "%s/%s", LOG_DIR, filename);
+  if (sdLoggingActive && strcmp(path, currentLogFileName) == 0) {
+    xSemaphoreGive(sdMutex);
+    return false;
+  }
+  bool result = SD.remove(path);
+  Serial.printf("[SD] Delete %s: %s\n", path, result ? "OK" : "FAIL");
+  xSemaphoreGive(sdMutex);
+  return result;
+}
+
+bool sdCardPresent() { return sdReady; }
diff --git a/sdcard_task.h b/sdcard_task.h
new file mode 100644
index 0000000..81b6189
--- /dev/null
+++ b/sdcard_task.h
@@ -0,0 +1,23 @@
+#ifndef SDCARD_TASK_H
+#define SDCARD_TASK_H
+
+#include <Arduino.h>
+#include <SPI.h>
+#include <SD.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include "config.h"
+
+extern volatile bool sdLoggingActive;
+extern char currentLogFileName[64];
+
+void sdTaskInit();
+void sdLoggingTask(void *param);
+bool sdCreateNewLogFile();
+void sdStopLogging();
+void sdStartLogging();
+String sdGetFileList();
+bool sdDeleteFile(const char *filename);
+bool sdCardPresent();
+
+#endif