stm32/boards/PYBD_SFx: Automatically turn on EN_3V3 when powering SD/MMC
#define MICROPY_BOARD_ENTER_STOP board_sleep(1);
#define MICROPY_BOARD_LEAVE_STOP board_sleep(0);
#define MICROPY_BOARD_ENTER_STANDBY board_sleep(1);
+#define MICROPY_BOARD_SDCARD_POWER mp_hal_pin_high(pyb_pin_EN_3V3);
void board_early_init(void);
void board_sleep(int value);
