Added test util for sending frames

Adjusted timeouts for slow uarts

README.md

@@ -77,7 +77,7 @@ Initial value: 0x0
     unless it is currently receiving a frame.
 - Collision detection on the sender side is done by reading back each sent byte.
 - Collision checking on receiver side, is done by checking the CRC and frame header.
-- If a frame has been started and there are no new bytes received for 20ms,
+- If a frame has been started and there are no new bytes received for 50ms,
     the frame is considered timed out and all received data can be dropped.
 - Incoming messages are stored in a fifo until the application retrieves them.
 - The receive fifo has a size of at least 2 messages.

software/testutils/send.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python2
+
+import sys
+import serial
+import crcmod.predefined
+
+
+def send_byte(ser, byte):
+    ser.reset_input_buffer()
+    ser.write(byte)
+    read_byte = ser.read()
+    if read_byte != byte:
+        print "Written %s read %s" % (hex(ord(read_byte)), hex(ord(byte)))
+        sys.exit(-1)
+
+
+
+def main():
+    if len(sys.argv) != 3:
+        print "Usage %s <port> <payload>" % (sys.argv[0])
+        sys.exit(-1)
+
+    payload = sys.argv[2]
+    payload += chr(0) * (16 - len(payload))
+
+    ser = serial.Serial(sys.argv[1], 9600, timeout=0.40)
+    crc = crcmod.predefined.Crc('crc-8-maxim')
+
+    send_byte(ser, chr(0xAA))
+    send_byte(ser, chr(0xFE))
+
+    for byte in payload:
+        crc.update(byte)
+        send_byte(ser, byte)
+
+    crc_sum = crc.digest()
+    send_byte(ser, crc_sum)
+
+    print "Send sucessfully !"
+
+if __name__ == '__main__':
+    main()

software/testutils/sniff.py

@@ -15,7 +15,7 @@ def hexdump(data):
 
 
 def main():
-    if len(sys.argv) < 2:
+    if len(sys.argv) != 2:
         print "Usage %s <port>" % (sys.argv[0])
         sys.exit(-1)