lab1: implement UART reader alongside with the file writer usage example

agent/uart-saver/FileWriter.py

@@ -0,0 +1,16 @@
+from UARTReader import UARTReader
+import os
+
+PORT = os.environ.get("PORT", None) or "/dev/ttyUSB0"
+FILE = os.environ.get("FILE", None) or "savefile.csv"
+
+r = UARTReader(PORT)
+
+with open(FILE, "w") as f:
+    f.write("x,y,z\n")
+
+    for i in range(500):
+        v = r.read_next()
+        f.write(",".join(tuple(map(str, v))) + "\n")
+
+r.close()

agent/uart-saver/UARTReader.py

@@ -0,0 +1,68 @@
+import os
+
+SUDO = os.environ.get("SUDO", None) or "sudo"
+
+class UARTReader:
+    def __init__(self, port = None):
+        if port == None:
+            # testing mode
+            pass
+        else:
+            # configure TTY
+            os.system(f"{SUDO} stty -F {port} 1:0:8bf:0:3:1c:7f:15:4:5:1:0:11:13:1a:0:12:f:17:16:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0")
+            self.port = open(port, "rb")
+
+            self.i = 0
+            self.d = 0
+            self.state = 0
+            self.data = bytearray(6)
+
+    def close(self):
+        self.port.close()
+
+    def __to_int(self, x):
+        if x >= 0x8000:
+            return x - 0x10000
+        else:
+            return x
+
+    def __frame_seek(self, byte):
+        if byte == 0xFF:
+            self.i += 1
+
+        if self.i >= 10 and byte != 0xFF:
+            self.i = 0
+
+            self.data[self.d] = byte
+            self.d = 1
+
+            self.state = 1
+
+    def __data_read(self, byte):
+        self.data[self.d] = byte
+
+        self.d += 1
+
+        if self.d >= 6:
+            self.d = 0
+            self.state = 2
+
+    def read_next(self):
+        while True:
+            b = self.port.read(1)
+
+            if not b:
+                self.close()
+                return None
+
+            if self.state == 0:
+                self.__frame_seek(b[0])
+            elif self.state == 1:
+                self.__data_read(b[0])
+
+            if self.state == 2:
+                self.state = 0
+
+                return (self.__to_int(self.data[0] + (self.data[1] << 8)),
+                        self.__to_int(self.data[2] + (self.data[3] << 8)),
+                        self.__to_int(self.data[4] + (self.data[5] << 8)))