Made tag uid retrieval awaitable.

software/src/mfrc522/main.py

@@ -1,13 +1,27 @@
 from mfrc522 import MFRC522
-import utime
+import asyncio
 
 
-def uid_to_string(uid):
-    mystring = "0x"
-    # The mfrc522 lib returns all tested uids in inverse order
-    for i in reversed(uid):
-        mystring += "%02X" % i
-    return mystring
+def uid_to_string(uid: list):
+    uid_string = "0x"
+    for i in uid:
+        uid_string += f'{i:02x}'
+    return uid_string
+
+
+async def get_tag_uid(reader: MFRC522, poll_interval_ms: int = 50) -> list:
+    while True:
+        reader.init()
+
+        # For now we omit the tag type
+        (stat, _) = reader.request(reader.REQIDL)
+        if stat == reader.OK:
+            (stat, uid) = reader.SelectTagSN()
+            if stat == reader.OK:
+                return uid
+
+        await asyncio.sleep_ms(poll_interval_ms)
+
 
 def main():
     reader = MFRC522(spi_id=1,sck=10,miso=12,mosi=11,cs=13,rst=9)
@@ -16,30 +30,8 @@ def main():
     print("Please place card on reader")
     print("")
 
-    previous_uid = [0]
-
-    try:
-        while True:
-            reader.init()
-
-            # For now we omit the tag type
-            (stat, _) = reader.request(reader.REQIDL)
-            if stat == reader.OK:
-                (stat, uid) = reader.SelectTagSN()
-                if uid == previous_uid:
-                    continue
-                if stat == reader.OK:
-                    print(uid_to_string(uid))
-
-                    previous_uid = uid
-                else:
-                    pass
-            else:
-                previous_uid=[0]
-            utime.sleep_ms(50)
-
-    except KeyboardInterrupt:
-        pass
+    uid = asyncio.run(get_tag_uid(reader))
+    print(f"Found tag with uid {uid_to_string(uid)}")
 
 if __name__ == "__main__":
     main()