diff --git a/ChangeLog b/ChangeLog
index 2f2ad09..3c3fdfe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2017-11-14  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* usb_lld.h (DEVICE_STATE): Add prefix USB_DEVICE_STATE_.
+	(USB_DEVICE_STATE_DEFAULT): New.
+
+	* mcu/usb-stm32f103.c (usb_lld_init): Suspend/resume init.
+	(usb_lld_event_handler): Add suspend/resume support.
+
+	* example-cdc/usb-cdc.c: Follow the change of usb_lld.h.
+	* example-cdc-gnu-linux/usb-cdc.c: Ditto.
+	* example-fs-bb48/usb-cdc.c: Ditto.
+	* example-fraucheky/main.c: Ditto.
+
 2017-11-13  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* mcu/usb-stm32f103.c (usb_lld_init): Set up interrupt on errors.
diff --git a/example-cdc-gnu-linux/usb-cdc.c b/example-cdc-gnu-linux/usb-cdc.c
index 4370295..97e6e3c 100644
--- a/example-cdc-gnu-linux/usb-cdc.c
+++ b/example-cdc-gnu-linux/usb-cdc.c
@@ -244,7 +244,7 @@ usb_device_reset (struct usb_dev *dev)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = ATTACHED;
+  tty0.device_state = USB_DEVICE_STATE_ATTACHED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
   chopstx_mutex_unlock (&tty0.mtx);
 }
@@ -414,7 +414,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (dev, i, 0);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = CONFIGURED;
+      tty0.device_state = USB_DEVICE_STATE_CONFIGURED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -427,7 +427,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (dev, i, 1);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = ADDRESSED;
+      tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -645,7 +645,7 @@ tty_open (void)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = UNCONNECTED;
+  tty0.device_state = USB_DEVICE_STATE_UNCONNECTED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
 
   chopstx_create (PRIO_TTY, STACK_ADDR_TTY, STACK_SIZE_TTY, tty_main, &tty0);
@@ -732,7 +732,7 @@ tty_main (void *arg)
 		 * OK.
 		 */
 		chopstx_mutex_lock (&tty0.mtx);
-		tty0.device_state = ADDRESSED;
+		tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
 		chopstx_cond_signal (&tty0.cnd);
 		chopstx_mutex_unlock (&tty0.mtx);
 		continue;
@@ -788,7 +788,7 @@ tty_main (void *arg)
 	}
 
       chopstx_mutex_lock (&t->mtx);
-      if (t->device_state == CONFIGURED && t->flag_connected
+      if (t->device_state == USB_DEVICE_STATE_CONFIGURED && t->flag_connected
 	  && t->flag_send_ready)
 	{
 	  uint8_t line[32];
@@ -812,7 +812,7 @@ void
 tty_wait_configured (struct tty *t)
 {
   chopstx_mutex_lock (&t->mtx);
-  while (t->device_state != CONFIGURED)
+  while (t->device_state != USB_DEVICE_STATE_CONFIGURED)
     chopstx_cond_wait (&t->cnd, &t->mtx);
   chopstx_mutex_unlock (&t->mtx);
 }
diff --git a/example-cdc/usb-cdc.c b/example-cdc/usb-cdc.c
index 1d5a64b..e590728 100644
--- a/example-cdc/usb-cdc.c
+++ b/example-cdc/usb-cdc.c
@@ -248,7 +248,7 @@ usb_device_reset (struct usb_dev *dev)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = ATTACHED;
+  tty0.device_state = USB_DEVICE_STATE_ATTACHED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
   chopstx_mutex_unlock (&tty0.mtx);
 }
@@ -417,7 +417,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (i, 0);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = CONFIGURED;
+      tty0.device_state = USB_DEVICE_STATE_CONFIGURED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -430,7 +430,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (i, 1);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = ADDRESSED;
+      tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -656,7 +656,7 @@ tty_open (void)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = UNCONNECTED;
+  tty0.device_state = USB_DEVICE_STATE_UNCONNECTED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
 
   chopstx_create (PRIO_TTY, STACK_ADDR_TTY, STACK_SIZE_TTY, tty_main, &tty0);
@@ -743,7 +743,7 @@ tty_main (void *arg)
 		 * OK.
 		 */
 		chopstx_mutex_lock (&tty0.mtx);
-		tty0.device_state = ADDRESSED;
+		tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
 		chopstx_cond_signal (&tty0.cnd);
 		chopstx_mutex_unlock (&tty0.mtx);
 		continue;
@@ -799,7 +799,7 @@ tty_main (void *arg)
 	}
 
       chopstx_mutex_lock (&t->mtx);
-      if (t->device_state == CONFIGURED && t->flag_connected
+      if (t->device_state == USB_DEVICE_STATE_CONFIGURED && t->flag_connected
 	  && t->flag_send_ready)
 	{
 	  uint8_t line[32];
@@ -823,7 +823,7 @@ void
 tty_wait_configured (struct tty *t)
 {
   chopstx_mutex_lock (&t->mtx);
-  while (t->device_state != CONFIGURED)
+  while (t->device_state != USB_DEVICE_STATE_CONFIGURED)
     chopstx_cond_wait (&t->cnd, &t->mtx);
   chopstx_mutex_unlock (&t->mtx);
 }
diff --git a/example-fraucheky/main.c b/example-fraucheky/main.c
index d4048f9..37ffd39 100644
--- a/example-fraucheky/main.c
+++ b/example-fraucheky/main.c
@@ -11,7 +11,7 @@
 
 static chopstx_mutex_t usb_mtx;
 static chopstx_cond_t usb_cnd;
-static uint32_t bDeviceState = UNCONNECTED; /* USB device status */
+static uint32_t bDeviceState = USB_DEVICE_STATE_UNCONNECTED;
 
 extern void EP6_IN_Callback (uint16_t len);
 extern void EP6_OUT_Callback (uint16_t len);
@@ -47,7 +47,7 @@ usb_device_reset (struct usb_dev *dev)
 
   /* Notify upper layer.  */
   chopstx_mutex_lock (&usb_mtx);
-  bDeviceState = ATTACHED;
+  bDeviceState = USB_DEVICE_STATE_ATTACHED;
   chopstx_cond_signal (&usb_cnd);
   chopstx_mutex_unlock (&usb_mtx);
 }
@@ -95,7 +95,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	setup_endpoints_for_interface (dev, i, 0);
       chopstx_mutex_lock (&usb_mtx);
-      bDeviceState = CONFIGURED;
+      bDeviceState = USB_DEVICE_STATE_CONFIGURED;
       chopstx_mutex_unlock (&usb_mtx);
     }
   else if (current_conf != dev->dev_req.value)
@@ -107,7 +107,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	setup_endpoints_for_interface (dev, i, 1);
       chopstx_mutex_lock (&usb_mtx);
-      bDeviceState = ADDRESSED;
+      bDeviceState = USB_DEVICE_STATE_ADDRESSED;
       chopstx_cond_signal (&usb_cnd);
       chopstx_mutex_unlock (&usb_mtx);
     }
@@ -206,7 +206,7 @@ usb_main (void *arg)
 
 	      case USB_EVENT_DEVICE_ADDRESSED:
 		chopstx_mutex_lock (&usb_mtx);
-		bDeviceState = ADDRESSED;
+		bDeviceState = USB_DEVICE_STATE_ADDRESSED;
 		chopstx_cond_signal (&usb_cnd);
 		chopstx_mutex_unlock (&usb_mtx);
 		continue;
@@ -304,16 +304,16 @@ main (int argc, char **argv)
   chopstx_mutex_init (&usb_mtx);
   chopstx_cond_init (&usb_cnd);
 
-  bDeviceState = UNCONNECTED;
+  bDeviceState = USB_DEVICE_STATE_UNCONNECTED;
   usb_thd = chopstx_create (PRIO_USB, STACK_ADDR_USB, STACK_SIZE_USB,
 			    usb_main, NULL);
-  while (bDeviceState != CONFIGURED)
+  while (bDeviceState != USB_DEVICE_STATE_CONFIGURED)
     chopstx_usec_wait (250*1000);
   fraucheky_main ();
   chopstx_cancel (usb_thd);
   chopstx_join (usb_thd, NULL);
   usb_lld_shutdown ();
-  bDeviceState = UNCONNECTED;
+  bDeviceState = USB_DEVICE_STATE_UNCONNECTED;
 
   return 0;
 }
diff --git a/example-fs-bb48/usb-cdc.c b/example-fs-bb48/usb-cdc.c
index a9a4a06..15b7cf6 100644
--- a/example-fs-bb48/usb-cdc.c
+++ b/example-fs-bb48/usb-cdc.c
@@ -245,7 +245,7 @@ usb_device_reset (struct usb_dev *dev)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = ATTACHED;
+  tty0.device_state = USB_DEVICE_STATE_ATTACHED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
   chopstx_mutex_unlock (&tty0.mtx);
 }
@@ -409,7 +409,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (dev, i, 0);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = CONFIGURED;
+      tty0.device_state = USB_DEVICE_STATE_CONFIGURED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -422,7 +422,7 @@ usb_set_configuration (struct usb_dev *dev)
       for (i = 0; i < NUM_INTERFACES; i++)
 	vcom_setup_endpoints_for_interface (dev, i, 1);
       chopstx_mutex_lock (&tty0.mtx);
-      tty0.device_state = ADDRESSED;
+      tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
       chopstx_cond_signal (&tty0.cnd);
       chopstx_mutex_unlock (&tty0.mtx);
     }
@@ -642,7 +642,7 @@ tty_open (void)
   tty0.flag_connected = 0;
   tty0.flag_send_ready = 1;
   tty0.flag_input_avail = 0;
-  tty0.device_state = UNCONNECTED;
+  tty0.device_state = USB_DEVICE_STATE_UNCONNECTED;
   memcpy (&tty0.line_coding, &line_coding0, sizeof (struct line_coding));
 
   chopstx_create (PRIO_TTY, STACK_ADDR_TTY, STACK_SIZE_TTY, tty_main, &tty0);
@@ -732,7 +732,7 @@ tty_main (void *arg)
 		 * OK.
 		 */
 		chopstx_mutex_lock (&tty0.mtx);
-		tty0.device_state = ADDRESSED;
+		tty0.device_state = USB_DEVICE_STATE_ADDRESSED;
 		chopstx_cond_signal (&tty0.cnd);
 		chopstx_mutex_unlock (&tty0.mtx);
 		continue;
@@ -788,7 +788,7 @@ tty_main (void *arg)
 	}
 
       chopstx_mutex_lock (&t->mtx);
-      if (t->device_state == CONFIGURED && t->flag_connected
+      if (t->device_state == USB_DEVICE_STATE_CONFIGURED && t->flag_connected
 	  && t->flag_send_ready)
 	{
 	  uint8_t line[32];
@@ -812,7 +812,7 @@ void
 tty_wait_configured (struct tty *t)
 {
   chopstx_mutex_lock (&t->mtx);
-  while (t->device_state != CONFIGURED)
+  while (t->device_state != USB_DEVICE_STATE_CONFIGURED)
     chopstx_cond_wait (&t->cnd, &t->mtx);
   chopstx_mutex_unlock (&t->mtx);
 }
diff --git a/mcu/usb-stm32f103.c b/mcu/usb-stm32f103.c
index a97fdfc..b1a95ad 100644
--- a/mcu/usb-stm32f103.c
+++ b/mcu/usb-stm32f103.c
@@ -340,7 +340,7 @@ void usb_lld_init (struct usb_dev *dev, uint8_t feature)
   /* Clear Interrupt Status Register, and enable interrupt for USB */
   st103_set_istr (0);
   st103_set_cntr (CNTR_CTRM | CNTR_OVRM | CNTR_ERRM
-		  | CNTR_RESETM);
+		  | CNTR_WKUPM | CNTR_SUSPM | CNTR_RESETM);
 }
 
 void usb_lld_prepare_shutdown (void)
@@ -368,6 +368,18 @@ usb_lld_event_handler (struct usb_dev *dev)
       st103_set_istr (CLR_RESET);
       return USB_MAKE_EV (USB_EVENT_DEVICE_RESET);
     }
+  else if ((istr_value & ISTR_WKUP))
+    {
+      st103_set_istr (CLR_WKUP);
+      *CNTR &= ~CNTR_FSUSP;
+      return USB_MAKE_EV (USB_EVENT_DEVICE_WAKEUP);
+    }
+  else if ((istr_value & ISTR_SUSP))
+    {
+      st103_set_istr (CLR_SUSP);
+      *CNTR |= (CNTR_FSUSP | CNTR_LPMODE);
+      return USB_MAKE_EV (USB_EVENT_DEVICE_SUSPEND);
+    }
   else
     {
       if ((istr_value & ISTR_OVR))
diff --git a/usb_lld.h b/usb_lld.h
index a24b45a..ce08f73 100644
--- a/usb_lld.h
+++ b/usb_lld.h
@@ -84,12 +84,13 @@ enum {
 };
 
 enum DEVICE_STATE {
-  UNCONNECTED,
-  ATTACHED,
-  POWERED,
-  SUSPENDED,
-  ADDRESSED,
-  CONFIGURED
+  USB_DEVICE_STATE_UNCONNECTED = 0,  /* No USB */
+  USB_DEVICE_STATE_ATTACHED    = 1,
+  USB_DEVICE_STATE_POWERED     = 2,
+  USB_DEVICE_STATE_DEFAULT     = 3,
+  USB_DEVICE_STATE_ADDRESSED   = 4,
+  USB_DEVICE_STATE_CONFIGURED  = 5,
+  USB_DEVICE_STATE_SUSPEND     = 128 /* Or-ed to other states */
 };
 
 void usb_lld_init (struct usb_dev *dev, uint8_t feature);