mirror of
https://github.com/DJ2LS/FreeDATA
synced 2024-05-14 08:04:33 +00:00
136 lines
4.2 KiB
Python
136 lines
4.2 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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Created on Sun Dec 13 13:45:58 2020
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@author: parallels
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"""
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import ctypes
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from ctypes import *
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import pathlib
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import binascii #required for string.to_bytes() function
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#import codecs
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import crcengine # required for CRC checksum
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#import struct
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import sys
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#sys.stdout.reconfigure(encoding='utf-8')
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def main():
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modem = FreeDV() #Load FreeDV Class as "modem"
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data = b'TEST' #byte string which will be send
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#data = bytes(62) #byte string with XX of zeros
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modulated_data = modem.Modulate(data) #Call Modulate function, which returns modulated data
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#print(modulated_data)
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###################### try: / except necessary beacuse of error 32 - BrokenPipeError while piping data
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try:
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#print(bytes(8)) #additional zero bytes before modulated data
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#sys.stdout.buffer.write(modulated_data) # the normal way of piping data
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#sys.stdout.flush() # flushing data
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print(bytes(32) + modulated_data, flush=True) #print modulated data with print function
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except (BrokenPipeError, IOError):
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print ('TEST BrokenPipeError caught', file = sys.stderr)
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#sys.stderr.close()
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class FreeDV():
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def __init__(self):
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libname = pathlib.Path().absolute() / "libcodec2.so"
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self.c_lib = ctypes.CDLL(libname) # Load FreeDV shared libary
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self.freedv = self.c_lib.freedv_open(12) #Set FreeDV waveform ( 10,11,12 --> DATA1-3 )
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self.bytes_per_frame = int(self.c_lib.freedv_get_bits_per_modem_frame(self.freedv)/8) #get bytes per frame from selected waveform
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self.payload_per_frame = self.bytes_per_frame -2 #get frame payload because of 2byte CRC16 checksum
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###################### CHECKSUM COMPARISON FREEDV VS CRCENGINE ########
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#https://crccalc.com
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teststring = b'123456789'
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# freedv crc16 checksum
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crctest2 = c_ushort(self.c_lib.freedv_gen_crc16(teststring, len(teststring)))
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print("FREEDV2: " + str(crctest2.value) + " = " + hex(crctest2.value)) #7450
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#Python crc16 checksum
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crc_algorithm = crcengine.new('crc16-ccitt-false') #load crc16 library
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crctest3 = crc_algorithm(teststring)
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print("CRCENGINE: " + str(crctest3) + " = " + hex(crctest3)) #8134
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#######################################################################
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# MODULATION-OUT OBJECT
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def ModulationOut(self):
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#return (c_short * self.c_lib.freedv_get_n_nom_modem_samples(self.freedv)) ## all other modes
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return (c_ubyte * self.c_lib.freedv_get_n_nom_modem_samples(self.freedv)) ## DATA modes
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# Pointer for changing buffer data type
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def FrameBytes(self):
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return (ctypes.c_ubyte * self.bytes_per_frame)
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# Modulate function which returns modulated data
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def Modulate(self,data_out):
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## mod_out = self.ModulationOut()() # new modulation object and get pointer to it
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## #self.freedv_rawdatapreambletx(self.freedv, mod_out) # SEND PREAMBLE
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##########################################
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mod_out = self.ModulationOut()() # new modulation object and get pointer to it
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#buffer = bytearray(self.bytes_per_frame) # use this if no CRC16 checksum is required
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buffer = bytearray(self.payload_per_frame) # puse this if CRC16 checksum is required ( DATA1-3)
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buffer[:len(data_out)] = data_out # set buffersize to length of data which will be send
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#buffer = self.scramble(buffer, packet_num)
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crc_algorithm = crcengine.new('crc16-ccitt-false') #load crc16 library
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crc = crc_algorithm(buffer) # get new crc16 from buffer
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#print(hex(crc))
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crc = crc.to_bytes(2, byteorder='big') # convert buffer to byte string
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buffer += crc # append crc16 to buffer
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#print(buffer)
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data = self.FrameBytes().from_buffer_copy(buffer) #change data format form bytearray to ctypes.u_byte
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#print(len(data))
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self.c_lib.freedv_rawdatatx(self.freedv,mod_out,data) # SEND DATA
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return bytes(mod_out) #return modulated data as byte string
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main()
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