diff --git a/pyusbtin/usbtin.py b/pyusbtin/usbtin.py
index 679353b..6aa5e0e 100644
--- a/pyusbtin/usbtin.py
+++ b/pyusbtin/usbtin.py
@@ -274,7 +274,11 @@ def rx_thread(self):
         while self.rx_thread_state == USBtin.RX_THREAD_RUNNING:
             # fetch bytes if available
             rxcount = self.serial_port.inWaiting()
-            if rxcount > 0:
+            if rxcount == 0:
+                # if no data is available, sleep for 10ms to avoid busy looping
+                sleep(0.01)
+                continue
+            else:
                 # fetch all data from serial buffer
                 buf = self.serial_port.read(rxcount)
                 if PY_VERSION == 2: