diff --git a/stm-firmware/include/reflow-controller/sd.h b/stm-firmware/include/reflow-controller/sd.h
new file mode 100644
index 0000000..5233a71
--- /dev/null
+++ b/stm-firmware/include/reflow-controller/sd.h
@@ -0,0 +1,42 @@
+/* Reflow Oven Controller
+ *
+ * Copyright (C) 2022  Mario Hüttel <mario.huettel@gmx.net>
+ *
+ * This file is part of the Reflow Oven Controller Project.
+ *
+ * The reflow oven controller is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * GDSII-Converter 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 reflow oven controller project.
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+ #ifndef _SD_H_
+ #define _SD_H_
+
+#include <stdbool.h>
+#include <fatfs/ff.h>
+
+/**
+ * @brief Mount the SD card if available and not already mounted
+ * @param fs Filesystem to mount to.
+ * @return true if mounted, false if an error occured or the SD is not inserted and cannot be mounted
+ */
+bool mount_sd_card_if_avail(FATFS *fs);
+
+/**
+ * @brief Return whether an SD card is inserted and mounted
+ * 
+ * @return true SD inserted and mounted
+ * @return false No SD inserted or not mounted
+ */
+bool sd_card_is_mounted(void);
+
+#endif /* _SD_H_ */
\ No newline at end of file
diff --git a/stm-firmware/main.c b/stm-firmware/main.c
index d485043..5573003 100644
--- a/stm-firmware/main.c
+++ b/stm-firmware/main.c
@@ -32,13 +32,13 @@
 #include <reflow-controller/systick.h>
 #include <reflow-controller/adc-meas.h>
 #include <reflow-controller/digio.h>
-#include "fatfs/shimatta_sdio_driver/shimatta_sdio.h"
 #include <stm-periph/stm32-gpio-macros.h>
 #include <stm-periph/rcc-manager.h>
 #include <stm-periph/uart.h>
 #include <reflow-controller/periph-config/shell-uart-config.h>
 #include <reflow-controller/oven-driver.h>
 #include <fatfs/ff.h>
+#include <reflow-controller/sd.h>
 #include <reflow-controller/ui/gui.h>
 #include <reflow-controller/ui/shell.h>
 #include <reflow-controller/ui/shell-uart.h>
@@ -88,40 +88,6 @@ static inline void uart_gpio_config(void)
 #endif
 }
 
-/**
- * @brief Mount the SD card if available and not already mounted
- * @param mounted The current mounting state of the SD card
- * @return true if mounted, false if an error occured or the SD is not inserted and cannot be mounted
- */
-static bool mount_sd_card_if_avail(bool mounted)
-{
-	FRESULT res;
-	static uint8_t IN_SECTION(.ccm.bss) inserted_counter = 0;
-
-	if (sdio_check_inserted() && mounted) {
-		memset(fs_ptr, 0, sizeof(FATFS));
-		sdio_stop_clk();
-		inserted_counter = 0;
-		return false;
-	}
-
-	if (!sdio_check_inserted() && inserted_counter < 255)
-		inserted_counter++;
-
-	if (!sdio_check_inserted() && !mounted && inserted_counter > 4) {
-		inserted_counter = 0;
-		res = f_mount(fs_ptr, "0:/", 1);
-		if (res == FR_OK) {
-			led_set(1, 1);
-			return true;
-		} else {
-			return false;
-		}
-	}
-
-	return mounted;
-}
-
 /**
  * @brief Process the boot status structure in the safety (backup) RAM
  * Depending on the flags set there, this function will:
@@ -315,7 +281,7 @@ int main(void)
 		if (systick_ticks_have_passed(quarter_sec_timestamp, 250)) {
 			led_set(1u, 0);
 			sd_old = sd_card_mounted;
-			sd_card_mounted = mount_sd_card_if_avail(sd_card_mounted);
+			sd_card_mounted = mount_sd_card_if_avail(fs_ptr);
 
 			if (sd_card_mounted && !sd_old) {
 				adc_pt1000_get_resistance_calibration(NULL, NULL, &cal_active);
diff --git a/stm-firmware/sd.c b/stm-firmware/sd.c
new file mode 100644
index 0000000..c061231
--- /dev/null
+++ b/stm-firmware/sd.c
@@ -0,0 +1,62 @@
+/* Reflow Oven Controller
+ *
+ * Copyright (C) 2022  Mario Hüttel <mario.huettel@gmx.net>
+ *
+ * This file is part of the Reflow Oven Controller Project.
+ *
+ * The reflow oven controller is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * GDSII-Converter 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 reflow oven controller project.
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+ 
+#include <reflow-controller/sd.h>
+#include "fatfs/ff.h"
+#include "fatfs/shimatta_sdio_driver/shimatta_sdio.h"
+#include <stdint.h>
+#include <helper-macros/helper-macros.h>
+#include <reflow-controller/digio.h>
+
+static bool sd_card_mounted_state = false;
+
+bool mount_sd_card_if_avail(FATFS *fs)
+{
+	FRESULT res;
+	static uint8_t IN_SECTION(.ccm.bss) inserted_counter = 0;
+
+	if (sdio_check_inserted() && sd_card_mounted_state) {
+		memset(fs, 0, sizeof(FATFS));
+		sdio_stop_clk();
+		inserted_counter = 0;
+		return false;
+	}
+
+	if (!sdio_check_inserted() && inserted_counter < 255)
+		inserted_counter++;
+
+	if (!sdio_check_inserted() && !sd_card_mounted_state && inserted_counter > 4) {
+		inserted_counter = 0;
+		res = f_mount(fs, "0:/", 1);
+		if (res == FR_OK) {
+			led_set(1, 1);
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	return sd_card_mounted_state;
+}
+
+bool sd_card_is_mounted(void)
+{
+	return sd_card_mounted_state;
+}
\ No newline at end of file