Sleep instead of busy-wait, approx 50% power reduction!

Downstream/Src/main.c

@@ -52,6 +52,8 @@ void CheckFirmwareMatchesHardware(void);
 
 int main(void)
 {
+    uint32_t iterationCount = 0;
+
     //First things first!
     DisableFlashWrites();
     CheckFirmwareMatchesHardware();
@@ -74,6 +76,15 @@ int main(void)
         USB_Host_Process();
         Downstream_SPIProcess();
         Downstream_PacketProcessor_CheckNotifyDisconnectReply();
+
+        //Some USB host state transitions take 3 iterations to fully apply.
+        //We'll be generous and give it 5 before sleeping.
+        iterationCount++;
+        if (iterationCount > 4)
+        {
+            iterationCount = 0;
+            __WFI();                //sleep time!
+        }
     }
 }
 

Upstream/Src/main.c

@@ -78,11 +78,12 @@ int main(void)
 
     while (1)
     {
-
+        __WFI();            //sleep time!
     }
 }
 
 
+
 void DisableFlashWrites(void)
 {
     //Disable flash writes until the next reset