flush to sd card before sleep

include/reset.h

@@ -8,6 +8,7 @@
 #include "lorawan.h"
 #include "display.h"
 #include "power.h"
+#include "sdcard.h"
 
 void reset_rtc_vars(void);
 void do_reset(bool warmstart);

include/sdcard.h

@@ -61,7 +61,8 @@
 #define SDCARD_FILE_HEADER_VOLTAGE ",voltage"
 #endif
 
-bool sdcard_init(void);
+bool sdcard_init(bool create = true);
+bool sdcard_close(void);
 void sdcardWriteData(uint16_t, uint16_t, uint16_t = 0);
 
 #endif // _SDCARD_H