Example #1
0
__interrupt void usb_general_interrupt()
#endif
{
   #if (USB_HOST_PIPE_INTERRUPT_TRANSFER == ENABLE)
   U8 i;
   U8 save_pipe_nb;
   #endif
// ---------- DEVICE events management -----------------------------------
#if (USB_DEVICE_FEATURE == ENABLED)

   // - Device start of frame received
   if (Is_usb_sof() && Is_sof_interrupt_enabled())
   {
      Usb_ack_sof();
      Usb_sof_action();
   }
#ifdef WA_USB_SUSPEND_PERTUBATION
  // - Device Suspend event (no more USB activity detected)
   if (Is_usb_suspend() && Is_suspend_interrupt_enabled())
   {
      usb_suspended=TRUE;
      Usb_ack_wake_up();                 // clear wake up to detect next event
      Usb_send_event(EVT_USB_SUSPEND);
      Usb_ack_suspend();
      Usb_enable_wake_up_interrupt();
      Usb_disable_resume_interrupt();
      Usb_freeze_clock();
      Stop_pll();
      Usb_suspend_action();
   }
  // - Wake up event (USB activity detected): Used to resume
   if (Is_usb_wake_up() && Is_wake_up_interrupt_enabled())
   {
      if(Is_pll_ready()==FALSE)
      {
         Pll_start_auto();
         Wait_pll_ready();
      }
      Usb_unfreeze_clock();
      Usb_ack_wake_up();
      if(usb_suspended)
      {
         Usb_enable_resume_interrupt();
         Usb_enable_reset_interrupt();
         while(Is_usb_wake_up())
         {
            Usb_ack_wake_up();
         }
         usb_delay_ms(2);
         if(Is_usb_sof() || Is_usb_resume() || Is_usb_reset() )
         {
            Usb_disable_wake_up_interrupt();
            Usb_wake_up_action();
            Usb_send_event(EVT_USB_WAKE_UP);
            Usb_enable_suspend_interrupt();
            Usb_enable_resume_interrupt();
            Usb_enable_reset_interrupt();
            
         }
         else // Workarround to make the USB enter power down mode again (spurious transcient detected on the USB lines)
         {
            Usb_ack_wake_up();                 // clear wake up to detect next event
            Usb_send_event(EVT_USB_SUSPEND);
            Usb_enable_wake_up_interrupt();
            Usb_disable_resume_interrupt();
            Usb_freeze_clock();
            Stop_pll();
            Usb_suspend_action();
         }
      }
   }
  // - Resume state bus detection
   if (Is_usb_resume() && Is_resume_interrupt_enabled())
   {
      usb_suspended = FALSE;
      Usb_disable_wake_up_interrupt();
      Usb_ack_resume();
      Usb_disable_resume_interrupt();
      Usb_resume_action();
      Usb_send_event(EVT_USB_RESUME);
   }
#else
  // - Device Suspend event (no more USB activity detected)
   if (Is_usb_suspend() && Is_suspend_interrupt_enabled())
   {
      // Remote wake-up handler
      if ((remote_wakeup_feature == ENABLED) && (usb_configuration_nb != 0))
      {
        Usb_disable_suspend_interrupt();
        Usb_ack_wake_up();
        Usb_enable_wake_up_interrupt();
        Stop_pll();
        Usb_freeze_clock();
        Usb_suspend_action();
        
        // After that user can execute "Usb_initiate_remote_wake_up()" to initiate a remote wake-up
        // Note that the suspend interrupt flag SUSPI must still be set to enable upstream resume
        // So the SUSPE enable bit must be cleared to avoid redundant interrupt
        // ****************
        // Please note also that is Vbus is lost during an upstream resume (Host disconnection),
        // the RMWKUP bit (used to initiate remote wake up and that is normally cleared by hardware when sent)
        // remains set after the event, so that a good way to handle this feature is :
        //            Usb_unfreeze_clock();
        //            Usb_initiate_remote_wake_up();
        //            while (Is_usb_pending_remote_wake_up())
        //            {
        //              if (Is_usb_vbus_low())
        //              {
        //                // Emergency action (reset macro, etc.) if Vbus lost during resuming
        //                break;
        //              }
        //            }
        //            Usb_ack_remote_wake_up_start();
        // ****************
      }
      else
      {
        // No remote wake-up supported
         Usb_ack_wake_up();                 // clear wake up to detect next event
         Usb_send_event(EVT_USB_SUSPEND);
         Usb_ack_suspend();  // must be executed last (after Usb_suspend_action()) to allow upstream resume
         Usb_enable_wake_up_interrupt();
         Usb_freeze_clock();
         Stop_pll();
         Usb_suspend_action();
      }
   }
  // - Wake up event (USB activity detected): Used to resume
   if (Is_usb_wake_up() && Is_wake_up_interrupt_enabled())
   {
      if(Is_pll_ready()==FALSE)
      {
         Pll_start_auto();
         Wait_pll_ready();
      }
      Usb_unfreeze_clock();
      Usb_ack_wake_up();
      Usb_disable_wake_up_interrupt();
      Usb_wake_up_action();
      Usb_send_event(EVT_USB_WAKE_UP);
      Usb_enable_suspend_interrupt();
   }
  // - Resume state bus detection
   if (Is_usb_resume() && Is_resume_interrupt_enabled())
   {
      Usb_disable_wake_up_interrupt();
      Usb_ack_resume();
      Usb_disable_resume_interrupt();
      Usb_resume_action();
      Usb_send_event(EVT_USB_RESUME);
   }
#endif
  // - USB bus reset detection
   if (Is_usb_reset()&& Is_reset_interrupt_enabled())
   {
      Usb_ack_reset();
      usb_init_device();
      Usb_reset_action();
      Usb_send_event(EVT_USB_RESET);
   }
#endif// End DEVICE FEATURE MODE

// ---------- HOST events management -----------------------------------
#if (USB_HOST_FEATURE == ENABLED && USB_DEVICE_FEATURE == ENABLED)
  // - ID pin change detection
   if(Is_usb_id_transition()&&Is_usb_id_interrupt_enabled())
   {
      if(Is_usb_id_device())
      { g_usb_mode=USB_MODE_DEVICE;}
      else
      { g_usb_mode=USB_MODE_HOST;}
      Usb_ack_id_transition();
      if( g_usb_mode != g_old_usb_mode) // Basic Debounce
      {
         if(Is_usb_id_device()) // Going to device mode
         {
            Usb_send_event(EVT_USB_DEVICE_FUNCTION);
         }
         else                   // Going to host mode
         {
            Usb_send_event(EVT_USB_HOST_FUNCTION);
         }
         Usb_id_transition_action();
         LOG_STR_CODE(log_id_change);
         #if ( ID_PIN_CHANGE_GENERATE_RESET == ENABLE)
         // Hot ID transition generates wdt reset
         wdtdrv_enable(WDTO_16MS);
         while(1);
         #endif
      }
   }
#endif
#if (USB_HOST_FEATURE == ENABLED)
  // - The device has been disconnected
   if(Is_device_disconnection() && Is_host_device_disconnection_interrupt_enabled())
   {
      host_disable_all_pipe();
      Host_ack_device_disconnection();
      device_state=DEVICE_DISCONNECTED;
      Usb_send_event(EVT_HOST_DISCONNECTION);
      init_usb_tree();      
      LOG_STR_CODE(log_device_disconnect);
      Host_device_disconnection_action();
   }
  // - Device connection
   if(Is_device_connection() && Is_host_device_connection_interrupt_enabled())
   {
      Host_ack_device_connection();
      host_disable_all_pipe();
      Host_device_connection_action();
   }
  // - Host Start of frame has been sent
   if (Is_host_sof() && Is_host_sof_interrupt_enabled())
   {
      Host_ack_sof();
      Usb_send_event(EVT_HOST_SOF);
      private_sof_counter++;
#if (USB_HUB_SUPPORT==ENABLE)
      hub_interrupt_sof++;
#endif

      // delay timeout management for interrupt tranfer mode in host mode
      #if ((USB_HOST_PIPE_INTERRUPT_TRANSFER==ENABLE) && (TIMEOUT_DELAY_ENABLE==ENABLE))
      if (private_sof_counter>=250)   // Count 1/4 sec
      {
         private_sof_counter=0;
         for(i=0;i<MAX_EP_NB;i++)
         {
            if(it_pipe_str[i].enable==ENABLE)
            {
               save_pipe_nb=Host_get_selected_pipe();
               Host_select_pipe(i);
               if((++it_pipe_str[i].timeout>TIMEOUT_DELAY) && (Host_get_pipe_type()!=TYPE_INTERRUPT))
               {
                  it_pipe_str[i].enable=DISABLE;
                  it_pipe_str[i].status=PIPE_DELAY_TIMEOUT;
                  Host_stop_pipe_interrupt(i);
                  if (is_any_interrupt_pipe_active()==FALSE)    // If no more transfer is armed
                  {
                     if (g_sav_int_sof_enable==FALSE)
                     {
                        Host_disable_sof_interrupt();
                     }
                  }
                  it_pipe_str[i].handle(PIPE_DELAY_TIMEOUT,it_pipe_str[i].nb_byte_processed);
               }
               Host_select_pipe(save_pipe_nb);
            }
         }
      }
      #endif  // (USB_HOST_PIPE_INTERRUPT_TRANSFER==ENABLE) && (TIMEOUT_DELAY_ENABLE==ENABLE))
      Host_sof_action();
   }
  // - Host Wake-up has been received
   if (Is_host_hwup() && Is_host_hwup_interrupt_enabled())
   {
      Host_disable_hwup_interrupt();  // Wake up interrupt should be disable host is now wake up !
      // CAUTION HWUP can be cleared only when USB clock is active (not frozen)!
      Pll_start_auto();               // First Restart the PLL for USB operation
      Wait_pll_ready();               // Get sure pll is lock
      Usb_unfreeze_clock();           // Enable clock on USB interface
      Host_ack_hwup();                // Clear HWUP interrupt flag
      Usb_send_event(EVT_HOST_HWUP);  // Send software event
      Host_hwup_action();             // Map custom action
   }
#endif // End HOST FEATURE MODE
}
Example #2
0
/**
 * @brief Entry point of the USB host management
 *
 * The aim is to manage the device target connection and enumeration
 * depending on the device_state, the function performs the required operations
 * to get the device enumerated and configured
 * Once the device is operationnal, the device_state value is DEVICE_READY
 * This state should be tested by the host task application before performing
 * any applicative requests to the device.
 *
 * @param none
 *
 * @return none
 *
 * \image html host_task.gif
 */
void usb_host_task(void)
{

   switch (device_state)
   {
     //------------------------------------------------------
     //   DEVICE_UNATTACHED state
     //
     //   - Default init state
     //   - Try to give device power supply
     //
      case DEVICE_UNATTACHED:
         Host_clear_device_supported();        // Reset Device status
         Host_clear_configured();
         Host_clear_device_ready();
         Usb_clear_all_event();                // Clear all software events
         new_device_connected=FALSE;
         selected_device=0;
         
#if (USB_HUB_SUPPORT==ENABLE)
         nb_hub_present = 0;
#endif         
         
#if (SOFTWARE_VBUS_CTRL==ENABLE)
         if( Is_usb_bconnection_error_interrupt()||Is_usb_vbus_error_interrupt())
         {
            Usb_ack_bconnection_error_interrupt();
            Usb_ack_vbus_error_interrupt();
            Host_clear_vbus_request();
         }
         Usb_disable_vbus_pad();
         Usb_enable_manual_vbus();
         if(Is_usb_srp_interrupt())
         {
            Usb_ack_srp_interrupt();
            Usb_enable_vbus_pad();
            Usb_enable_vbus();
            device_state=DEVICE_ATTACHED;
         }
#else
         Usb_enable_vbus();                    // Give at least device power supply!!!
         if(Is_usb_vbus_high())
         { device_state=DEVICE_ATTACHED; }     // If VBUS ok goto to device connection expectation
#endif
      break;

     //------------------------------------------------------
     //   DEVICE_ATTACHED state
     //
     //   - Vbus is on
     //   - Try to detected device connection
     //
      case DEVICE_ATTACHED :
         if (Is_device_connection() || (force_enumeration==TRUE))     // Device pull-up detected
         {
            Host_ack_device_connection();
            Host_clear_device_supported();        // Reset Device status
            Host_clear_configured();
            Host_clear_device_ready();
            Usb_clear_all_event();                // Clear all software events
            new_device_connected=FALSE;
            force_enumeration=FALSE;

           // Now device is connected, enable disconnection interrupt
            Host_enable_device_disconnection_interrupt();
            Enable_interrupt();
           // Reset device status
            Host_clear_device_supported();
            Host_clear_configured();
            Host_clear_device_ready();
            Host_enable_sof();            // Start Start Of Frame generation
            Host_enable_sof_interrupt();  // SOF will be detected under interrupt
            c = 0;
            while (c<100)               // wait 100ms before USB reset
            {
               if (Is_usb_event(EVT_HOST_SOF)) { Usb_ack_event(EVT_HOST_SOF); c++; }// Count Start Of frame
               if (Is_host_emergency_exit() || Is_usb_bconnection_error_interrupt()) {goto device_attached_error;}
            }
            Host_disable_device_disconnection_interrupt();
            Host_send_reset();          // First USB reset
            Usb_ack_event(EVT_HOST_SOF);
            while (Is_host_reset());    // Active wait of end of reset send
            Host_ack_reset();
            //Workaround for some bugly devices with powerless pull up
            //usually low speed where data line rise slowly and can be interpretaded as disconnection
            for(c=0;c!=0xFFFF;c++)    // Basic Timeout counter
            {
               if(Is_usb_event(EVT_HOST_SOF))   //If we detect SOF, device is still alive and connected, just clear false disconnect flag
               {
                  if(Is_device_disconnection())
                  {
                      Host_ack_device_connection();
                      Host_ack_device_disconnection();
                      break;
                  }
               }
            }
            Host_enable_device_disconnection_interrupt();
            // All USB pipes must be reconfigured after a USB reset generation
            host_configure_pipe(PIPE_CONTROL, \
                                            TYPE_CONTROL, \
                                            TOKEN_SETUP,  \
                                            EP_CONTROL,   \
                                            SIZE_64,      \
                                            ONE_BANK,     \
                                            0             );            
            c = 0;
            while (c<100)               // wait 100ms after USB reset
            {
               if (Is_usb_event(EVT_HOST_SOF)) { Usb_ack_event(EVT_HOST_SOF); c++; }// Count Start Of frame
               if (Is_host_emergency_exit() || Is_usb_bconnection_error_interrupt()) {goto device_attached_error;}
            }
            device_state = DEVICE_POWERED;
            c=0;
         }
         device_attached_error:
        // Device connection error, or vbus pb -> Retry the connection process from the begining
         if( Is_usb_bconnection_error_interrupt()||Is_usb_vbus_error_interrupt()||Is_usb_vbus_low())
         {
            Usb_ack_bconnection_error_interrupt();
            Usb_enable_vbus_hw_control();
            device_state=DEVICE_UNATTACHED;
            Usb_disable_vbus();
            Usb_disable_vbus_pad();
            Usb_enable_vbus_pad();
            Usb_ack_vbus_error_interrupt();
            Usb_enable_vbus();
            Usb_disable_vbus_hw_control();
            Host_disable_sof();
         }
         break;

     //------------------------------------------------------
     //   DEVICE_POWERED state
     //
     //   - Device connection (attach) as been detected,
     //   - Wait 100ms and configure default control pipe
     //
      case DEVICE_POWERED :
         LOG_STR_CODE(log_device_connected);
         Host_device_connection_action();
         if (Is_usb_event(EVT_HOST_SOF))
         {
            Usb_ack_event(EVT_HOST_SOF);
            if (c++ >= 100)                          // Wait 100ms
            {
               device_state = DEVICE_DEFAULT;
            }
         }
         break;

     //------------------------------------------------------
     //   DEVICE_DEFAULT state
     //
     //   - Get device descriptor
     //   - Reconfigure Pipe 0 according to Device EP0
     //   - Attribute device address
     //
      case DEVICE_DEFAULT :
        // Get first device descriptor
         Host_select_device(0);
         usb_tree.device[0].ep_ctrl_size=8;
         if( CONTROL_GOOD == host_get_device_descriptor_uncomplete())
         {
            c = 0;
            while(c<20)           // wait 20ms before USB reset (special buggly devices...)
            {
               if (Is_usb_event(EVT_HOST_SOF)) { Usb_ack_event(EVT_HOST_SOF); c++; }
               if (Is_host_emergency_exit() || Is_usb_bconnection_error_interrupt())  {break;}
            }
            Host_disable_device_disconnection_interrupt();
            Host_send_reset();          // First USB reset
            Usb_ack_event(EVT_HOST_SOF);
            while (Is_host_reset());    // Active wait of end of reset send
            Host_ack_reset();
            //Workaround for some bugly devices with powerless pull up
            //usually low speed where data line rise slowly and can be interpretaded as disconnection
            for(c=0;c!=0xFFFF;c++)    // Basic Timeout counter
            {
               if(Is_usb_event(EVT_HOST_SOF))   //If we detect SOF, device is still alive and connected, just clear false disconnect flag
               {
                  if(Is_device_disconnection())
                  {
                      Host_ack_device_connection();
                      Host_ack_device_disconnection();
                      break;
                  }
               }
            }
            Host_enable_device_disconnection_interrupt();
            c = 0;
            host_configure_pipe(PIPE_CONTROL, \
                                            TYPE_CONTROL, \
                                            TOKEN_SETUP,  \
                                            EP_CONTROL,   \
                                            SIZE_64,      \
                                            ONE_BANK,     \
                                            0             );            
            while(c<200)           // wait 200ms after USB reset
            {
               if (Is_usb_event(EVT_HOST_SOF)) { Usb_ack_event(EVT_HOST_SOF); c++; }
               if (Is_host_emergency_exit() || Is_usb_bconnection_error_interrupt())  {break;}
            }
            usb_tree.device[0].ep_ctrl_size=data_stage[OFFSET_FIELD_MAXPACKETSIZE];
            
            // Give an absolute device address
            host_set_address(DEVICE_BASE_ADDRESS);
            usb_tree.device[0].device_address=DEVICE_BASE_ADDRESS;
            device_state = DEVICE_ADDRESSED;
         }
         else
         {  device_state = DEVICE_ERROR; }
         break;

     //------------------------------------------------------
     //   DEVICE_BASE_ADDRESSED state
     //
     //   - Check if VID PID is in supported list
     //
      case DEVICE_ADDRESSED :
         if (CONTROL_GOOD == host_get_device_descriptor())
         {
           // Detect if the device connected belongs to the supported devices table
            if (HOST_TRUE == host_check_VID_PID())
            {
               Host_set_device_supported();
               Host_device_supported_action();
               device_state = DEVICE_CONFIGURED;
            }
            else
            {
               #if (HOST_STRICT_VID_PID_TABLE==ENABLE)
                  Host_device_not_supported_action();
                  device_state = DEVICE_ERROR;
               #else
                  device_state = DEVICE_CONFIGURED;
               #endif
            }
         }
         else // Can not get device descriptor
         {  device_state = DEVICE_ERROR; }
         break;

     //------------------------------------------------------
     //   DEVICE_CONFIGURED state
     //
     //   - Configure pipes for the supported interface
     //   - Send Set_configuration() request
     //   - Goto full operating mode (device ready)
     //
      case DEVICE_CONFIGURED :
         if (CONTROL_GOOD == host_get_configuration_descriptor())
         {
            if (HOST_FALSE != host_check_class()) // Class support OK?
            {
               usb_tree.nb_device++;
            #if (HOST_AUTO_CFG_ENDPOINT==ENABLE)
               if(host_auto_configure_endpoint())
            #else
               Host_set_configured();     // Assumes config is OK with user config
               if(User_configure_endpoint()) // User call here instead of autoconfig
            #endif
               {
                  if (CONTROL_GOOD== host_set_configuration(1))  // Send Set_configuration
                  {
                     //host_set_interface(interface_bound,interface_bound_alt_set);
                     // device and host are now fully configured
                     // goto DEVICE READY normal operation
                      device_state = DEVICE_READY;
                      Host_set_device_ready();
                     // monitor device disconnection under interrupt
                      Host_enable_device_disconnection_interrupt();
                     // If user host application requires SOF interrupt event
                     // Keep SOF interrupt enable otherwize, disable this interrupt
                  #if (HOST_CONTINUOUS_SOF_INTERRUPT==DISABLE && USB_HUB_SUPPORT==DISABLE)
                      Host_disable_sof_interrupt();
                  #endif
                  #if (USB_HUB_SUPPORT==ENABLE)
                      // Check if the connected device is a hub
                      if(Get_class(0)==HUB_CLASS && Get_subclass(0)==0x00 && Get_protocol(0)==0x00)
                      {
                           // Get hub descriptor
                           if( Get_hub_descriptor()==CONTROL_GOOD)
                           {
                              // Power each port of the hub
                              i=data_stage[NB_PORT_OFFSET];
                              for(c=1;c<=i;c++)
                              {
                                 Set_port_feature(PORT_POWER,c);
                              }
                              nb_hub_present = 1;
                              hub_device_address[0]=DEVICE_BASE_ADDRESS;
                              hub_init(nb_hub_present-1);    
                           }
                      }
                      else
                      {
                         nb_hub_present = 0;
                         new_device_connected=TRUE;
                      }
                  #else
                      new_device_connected=TRUE;
                  #endif
                      
                      Enable_interrupt();
                      LOG_STR_CODE(log_device_enumerated);
                  }
                  else// Problem during Set_configuration request...
                  {   device_state = DEVICE_ERROR;  }
               }
            }
            else // device class not supported...
            {
                device_state = DEVICE_ERROR;
                LOG_STR_CODE(log_device_unsupported);
                Host_device_class_not_supported_action();
            }
         }
         else // Can not get configuration descriptors...
         {  device_state = DEVICE_ERROR; }
         break;

     //------------------------------------------------------
     //   DEVICE_READY state
     //
     //   - Full std operatinf mode
     //   - Nothing to do...
     //
      case DEVICE_READY:     // Host full std operating mode!
         new_device_connected=FALSE;
         
      #if (USB_HUB_SUPPORT==ENABLE)
         f_hub_port_disconnect=FALSE;
         // If one hub is present in the USB tree and the period interval
         // for the interrupt hub endpoint occurs
         if(nb_hub_present && hub_interrupt_sof==0)
         {
            saved_device=selected_device;      // Backup user selected device
            for(j=1;j<=nb_hub_present;j++)
            {
               for(i=0;i<MAX_DEVICE_IN_USB_TREE;i++)
               {
                  if(usb_tree.device[i].device_address==hub_device_address[j-1]) break;
               }
               Host_select_device(i);
               Host_select_pipe(usb_tree.device[i].interface[0].ep[0].pipe_number);
               Host_ack_nak_received();
               Host_ack_in_received();
               Host_unfreeze_pipe();
               Host_send_in();
               while(1)
               {
                   if(Is_host_nak_received())   break;
                   if(Is_host_emergency_exit()) break;
                   if(Is_host_in_received())    break;
               }
               Host_freeze_pipe();
               if(Is_host_nak_received())
               {
                  Host_ack_nak_received();
               }
               if(Is_host_in_received())
               {
                  if(Is_host_stall()==FALSE)
                  {
                     c=Host_read_byte();
                  }
                  Host_ack_in_received();
                  hub_manage_port_change_status(c,j);
               }
            } // for all hub 
            Host_select_device(saved_device);  // Restore user selected device
            #if (USER_PERIODIC_PIPE==ENABLE)
            unfreeze_user_periodic_pipe();
            #endif
         }
      #endif
         break;

     //------------------------------------------------------
     //   DEVICE_ERROR state
     //
     //   - Error state
     //   - Do custom action call (probably go to default mode...)
     //
      case DEVICE_ERROR :    // TODO !!!!
      #if (HOST_ERROR_RESTART==ENABLE)
         device_state=DEVICE_UNATTACHED;
      #endif
         Host_device_error_action();
         break;

     //------------------------------------------------------
     //   DEVICE_SUSPENDED state
     //
     //   - Host application request to suspend the device activity
     //   - State machine comes here thanks to Host_request_suspend()
     //
      case DEVICE_SUSPENDED :
         if(Is_device_supports_remote_wakeup()) // If the connected device supports remote wake up
         {
           host_set_feature_remote_wakeup();    // Enable this feature...
         }
         LOG_STR_CODE(log_going_to_suspend);
         c = Is_host_sof_interrupt_enabled(); //Save current sof interrupt enable state
         Host_disable_sof_interrupt();
         Host_ack_sof();
         Host_disable_sof();           // Stop start of frame generation, this generates the suspend state
         Host_ack_hwup();
         Host_enable_hwup_interrupt(); // Enable host wake-up interrupt
                                       // (this is the unique USB interrupt able to wake up the CPU core from power-down mode)
         Usb_freeze_clock();
         Stop_pll();
         Host_suspend_action();              // Custom action here! (for example go to power-save mode...)
         device_state=DEVICE_WAIT_RESUME;    // wait for device resume event
         break;

     //------------------------------------------------------
     //   DEVICE_WAIT_RESUME state
     //
     //   - Wait in this state till the host receives an upstream resume from the device
     //   - or the host software request the device to resume
     //
      case DEVICE_WAIT_RESUME :
         if(Is_usb_event(EVT_HOST_HWUP)|| Is_host_request_resume())// Remote wake up has been detected
                                                                 // or Local resume request has been received
         {
            if(Is_host_request_resume())       // Not a remote wakeup, but an host application request
            {
               Host_disable_hwup_interrupt();  // Wake up interrupt should be disable host is now wake up !
              // CAUTION HWUP can be cleared only when USB clock is active
               Pll_start_auto();               // First Restart the PLL for USB operation
               Wait_pll_ready();               // Get sure pll is lock
               Usb_unfreeze_clock();           // Enable clock on USB interface
               Host_ack_hwup();                // Clear HWUP interrupt flag
            }
            Host_enable_sof();
            Host_send_resume();                            // Send down stream resume
            while (Is_host_down_stream_resume()==FALSE);   // Wait Down stream resume sent
            Host_ack_remote_wakeup();        // Ack remote wake-up reception
            Host_ack_request_resume();       // Ack software request
            Host_ack_down_stream_resume();   // Ack down stream resume sent
            Usb_ack_event(EVT_HOST_HWUP);    // Ack software event
            if(c) { Host_enable_sof_interrupt(); } // Restore SOF interrupt enable state before suspend
            device_state=DEVICE_READY;       // Come back to full operating mode
            LOG_STR_CODE(log_usb_resumed);
         }
         break;

     //------------------------------------------------------
     //   DEVICE_DISCONNECTED state
     //
     //   - Device disconnection has been detected
     //   - Run scheduler in this state at least two times to get sure event is detected by all host application tasks
     //   - Go to DEVICE_DISCONNECTED_ACK state before DEVICE_UNATTACHED, to get sure scheduler calls all app tasks...
     //
      case DEVICE_DISCONNECTED :
         device_state = DEVICE_DISCONNECTED_ACK;
         break;

     //------------------------------------------------------
     //   DEVICE_DISCONNECTED_ACK state
     //
     //   - Device disconnection has been detected and managed bu applicatives tasks
     //   - Go to DEVICE_UNATTACHED state
     //
      case DEVICE_DISCONNECTED_ACK :
         device_state = DEVICE_UNATTACHED;
         break;

     //------------------------------------------------------
     //   default state
     //
     //   - Default case: ERROR
     //   - Goto no device state
     //
      default :
         device_state = DEVICE_UNATTACHED;
         break;
      }
}