added input buffer flushing and fixed the timeout for the rfid reader

Author: timothywashburn

src/main.py

@@ -43,19 +43,18 @@ def myLoop(app, reader):
     last_time = 0
     scanner_error = False
     while True:
-        time.sleep(0.1)
-
         if scanner_error:
+            time.sleep(0.1)
             if reader.reconnect():
                 logging.info("Card reader reconnected")
                 scanner_error = False
             continue
 
         try:
             in_waiting = reader.getSerInWaiting()
-        except OSError:
+        except OSError as e:
             if not scanner_error:
-                logging.error("Card reader disconnected, disabling until reconnection")
+                logging.error("Card reader disconnected, disabling until reconnection: %s", e)
                 scanner_error = True
             continue
 

src/reader.py

@@ -26,8 +26,8 @@ def __init__(self, usb_id="/dev/ttyUSB0"):
         logging.info("Card reader init finished")
 
     def _init_pn532(self):
-        uart = serial.Serial(self._usb_id, baudrate=115200, timeout=1)
-        self._pn532 = PN532_UART(uart, debug=False)
+        uart = serial.Serial(self._usb_id, baudrate=115200, timeout=0.1)
+        self._pn532 = PN532_UART(uart, debug=True)
         self._pn532.SAM_configuration()
 
     def reconnect(self):
@@ -47,6 +47,8 @@ def getSerInWaiting(self):
             raise OSError(f"PN532 error: {e}")
         if uid:
             self._pending_tag = "".join(f"{b:02X}" for b in uid)
+            time.sleep(0.01) # let any remaining in-flight bytes arrive
+            self._pn532._uart.reset_input_buffer() # and flush them
             return expected_characters
         self._pending_tag = None
         return 0