Serial framing protocol
This library provides a way to frame and send data safely over serial, this include a corruption check.
How-to-use
Framing data
# The data to be framed
data = bytearray([0x12, 0x34, 0x56])
# Frame and store the result in framed_data
framed_data = bytearray()
frame_data(data, framed_data)
# Print the hexadecimal representation of the result
# This will return b'7e0003123456bf127f'
print(binascii.hexlify(framed_data))The actual byte sent are 0x7e 0x0 0x3 0x12 0x34 0x56 0xbf 0x12 0x7f.
In those bytes:
-
0x7eis the start of frame flag (1 byte) -
0x0 0x3is the data size (2 bytes) -
0x12 0x34is the data we are sending (n bytes) -
0xbf 0x12is the cyclic redundancy check (2 bytes), it helps checking for any corruption of the data -
0x7fis the end of frame flag (1 byte)
Unframing data
# The frame to unframe the data from
framed_data = bytearray([0x7e, 0x0, 0x3, 0x12, 0x34, 0x56, 0xbf, 0x12, 0x7f])
# Unframe and store the result in unframed_data
unframed_data = bytearray()
unframe_data(framed_data, unframed_data)
# Print the hexadecimal representation of the result
# This will return b'123456'
print(binascii.hexlify(unframed_data))