disable CFG_TUD_CDC_FLUSH_ON_SOF to prevent usbd overflow

lib/sdk11/components/libraries/bootloader_dfu/bootloader.c

@@ -128,6 +128,9 @@ static void wait_for_events(void)
         // USB stack
         tusb_task();
 
+        // Send out cdc's data
+        tud_cdc_flush();
+
         if ((m_update_status == BOOTLOADER_COMPLETE) ||
             (m_update_status == BOOTLOADER_TIMEOUT)  ||
             (m_update_status == BOOTLOADER_RESET))

src/segger/nrf52840_bootloader.emProject

@@ -167,7 +167,7 @@
         </folder>
       </folder>
       <folder Name="tinyusb">
-        <folder Name="tinyusb">
+        <folder Name="src">
           <file file_name="../../lib/tinyusb/src/tusb.c" />
           <file file_name="../../lib/tinyusb/src/tusb.h" />
           <file file_name="../../lib/tinyusb/src/tusb_hal.h" />

src/usb/tusb_config.h

@@ -75,11 +75,15 @@
  *------------------------------------------------------------------*/
 
 // FIFO size of CDC TX and RX
-#define CFG_TUD_CDC_BUFSIZE         1024
+#define CFG_TUD_CDC_RX_BUFSIZE      1024
+#define CFG_TUD_CDC_TX_BUFSIZE      1024
 
-// TX is sent automatically every Start of Frame event.
-// If not enabled, application must call tud_cdc_flush() periodically
-#define CFG_TUD_CDC_FLUSH_ON_SOF    1
+/* TX is sent automatically on every Start of Frame event ~ 1ms.
+ * If not enabled, application must call tud_cdc_flush() periodically
+ * Note: Enabled this could overflow device task, if it does, define
+ * CFG_TUD_TASK_QUEUE_SZ with large value
+ */
+#define CFG_TUD_CDC_FLUSH_ON_SOF    0
 
 // Number of supported Logical Unit Number
 #define CFG_TUD_MSC_MAXLUN          1