Adding support for a SOF callback

src/device/usbd.c

@@ -597,6 +597,10 @@ void tud_task_ext(uint32_t timeout_ms, bool in_isr)
       break;
 
       case DCD_EVENT_SOF:
+        TU_LOG_USBD("\r\n");
+        if ( tud_sof_cb ) tud_sof_cb(event->rhport, event->sof.frame_count);
+      break;
+
       default:
         TU_BREAKPOINT();
       break;

src/device/usbd.h

@@ -148,6 +148,9 @@ TU_ATTR_WEAK void tud_suspend_cb(bool remote_wakeup_en);
 // Invoked when usb bus is resumed
 TU_ATTR_WEAK void tud_resume_cb(void);
 
+// Invoked when a new (micro) frame started
+TU_ATTR_WEAK void tud_sof_cb(uint8_t rhport, uint32_t frame_count);
+
 // Invoked when received control request with VENDOR TYPE
 TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const * request);