From 891cc945770e54636096a55e78a54a740bdd7bf0 Mon Sep 17 00:00:00 2001
From: liang <466175335@qq.com>
Date: Sun, 29 Sep 2019 02:15:15 -0700
Subject: [PATCH] AP_Bootloader: check VBUS for fast boot

---
 Tools/AP_Bootloader/AP_Bootloader.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Tools/AP_Bootloader/AP_Bootloader.cpp b/Tools/AP_Bootloader/AP_Bootloader.cpp
index 1ce163b47e..96023a1bef 100644
--- a/Tools/AP_Bootloader/AP_Bootloader.cpp
+++ b/Tools/AP_Bootloader/AP_Bootloader.cpp
@@ -107,7 +107,15 @@ int main(void)
         timeout = 0;
     }
 #endif
-    
+#if defined(HAL_GPIO_PIN_VBUS) && defined(HAL_ENABLE_VBUS_CHECK)
+#if HAL_USE_SERIAL_USB == TRUE
+    else if (palReadLine(HAL_GPIO_PIN_VBUS) == 0)  {
+        try_boot = true;
+        timeout = 0;
+    }
+#endif
+#endif
+
     // if we fail to boot properly we want to pause in bootloader to give
     // a chance to load new app code
     set_fast_reboot(RTC_BOOT_OFF);