diff --git a/examples/device/dfu/src/main.c b/examples/device/dfu/src/main.c
index fb3c22630..d4e75a44b 100644
--- a/examples/device/dfu/src/main.c
+++ b/examples/device/dfu/src/main.c
@@ -45,6 +45,7 @@
 #include "bsp/board_api.h"
 #include "tusb.h"
 
+#include "device/dcd.h"
 //--------------------------------------------------------------------+
 // MACRO CONSTANT TYPEDEF PROTYPES
 //--------------------------------------------------------------------+
@@ -65,6 +66,7 @@ enum {
 static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
 
 void led_blinking_task(void);
+static void musb_test(void);
 
 /*------------- MAIN -------------*/
 int main(void) {
@@ -79,6 +81,7 @@ int main(void) {
   while (1) {
     tud_task(); // tinyusb device task
     led_blinking_task();
+    musb_test();
   }
 }
 
@@ -86,6 +89,26 @@ int main(void) {
 // Device callbacks
 //--------------------------------------------------------------------+
 
+// on off usb interrupt 20ms for testing
+static void musb_test(void) {
+  static uint32_t start_ms  = 0;
+  static bool irq_enabled = true;
+
+  if (tusb_time_millis_api() - start_ms < 20) {
+    return; // not enough time
+  }
+
+  if (irq_enabled) {
+    dcd_int_disable(0);
+    tusb_time_delay_ms_api(20);
+    dcd_int_enable(0);
+  } else {
+  }
+
+  irq_enabled = !irq_enabled;
+  start_ms += 20;
+}
+
 // Invoked when device is mounted
 void tud_mount_cb(void) {
   blink_interval_ms = BLINK_MOUNTED;
@@ -122,7 +145,7 @@ uint32_t tud_dfu_get_timeout_cb(uint8_t alt, uint8_t state) {
     // For this example
     // - Atl0 Flash is fast : 1   ms
     // - Alt1 EEPROM is slow: 100 ms
-    return (alt == 0) ? 1 : 100;
+    return (alt == 0) ? 0 : 0;
   } else if (state == DFU_MANIFEST) {
     // since we don't buffer entire image and do any flashing in manifest stage
     return 0;
@@ -142,9 +165,9 @@ void tud_dfu_download_cb(uint8_t alt, uint16_t block_num, const uint8_t *data, u
 
   //printf("\r\nReceived Alt %u BlockNum %u of length %u\r\n", alt, wBlockNum, length);
 
-  for (uint16_t i = 0; i < length; i++) {
-    printf("%c", data[i]);
-  }
+  //for (uint16_t i = 0; i < length; i++) {
+  //  printf("%c", data[i]);
+  //}
 
   // flashing op for download complete without error
   tud_dfu_finish_flashing(DFU_STATUS_OK);