mdb: Make raspi backend blocking

mdb/backend.py

@@ -58,8 +58,12 @@ class RaspiBackend(Backend):
             raise Exception('Port open failed: %d', status)
 
     def read(self):
-        _, data = self.pi.bb_serial_read(self.rx_pin)
-        return data
+        while True:
+            cnt, data = self.pi.bb_serial_read(self.rx_pin)
+            if cnt <= 0:
+                time.sleep(0.001)
+            else:
+                return data
 
     def write(self, data):
         self.pi.wave_add_serial(self.tx_pin, 9600, data, bb_bits=9, bb_stop=6)
@@ -69,7 +73,7 @@ class RaspiBackend(Backend):
         self.pi.wave_send_once(wid)   # transmit serial data
 
         while self.pi.wave_tx_busy(): # wait until all data sent
-            pass
+            time.sleep(0.001)
 
         self.pi.wave_delete(wid)
         self.pi.set_mode(self.tx_pin, pigpio.INPUT)

requirements.txt

@@ -18,4 +18,4 @@ websocket-client==0.40.0
 Werkzeug==0.11.15
 WTForms==2.1
 blinker>=1.3
--e git+https://code.hackerspace.pl/informatic/flask-spaceauth#egg=Flask-SpaceAuth
+git+https://code.hackerspace.pl/informatic/flask-spaceauth#egg=Flask-SpaceAuth