mirror of
https://github.com/DJ2LS/FreeDATA
synced 2024-05-14 08:04:33 +00:00
83 lines
No EOL
3.3 KiB
Python
83 lines
No EOL
3.3 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: DJ2LS
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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 sys
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def main():
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modem = FreeDV() #Load FreeDV Class as "modem"
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data = b'HALLO' #byte string which will be send
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modulated_data = modem.Modulate(data) #Call Modulate function, which modulates data and prints it to the terminal
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class FreeDV():
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def __init__(self):
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self.mode = 12 # define mode
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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(self.mode) #Set FreeDV waveform ( 10,11,12 --> DATAC1-3 )
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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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self.n_tx_modem_samples = self.c_lib.freedv_get_n_tx_modem_samples(self.freedv)*2 #get n_tx_modem_samples which defines the size of the modulation object
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# MODULATION-OUT OBJECT
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def ModulationOut(self):
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return (c_short * self.n_tx_modem_samples) ##
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# Pointer for changing buffer data type
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def FrameBytes(self):
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return (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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data_list = [data_out[i:i+self.payload_per_frame] for i in range(0, len(data_out), self.payload_per_frame)] # split incomming bytes to size of 30bytes, create a list and loop through it
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data_list_length = len(data_list)
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for i in range(data_list_length): # LOOP THROUGH DATA LIST
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if self.mode < 10: # don't generate CRC16 for modes 0 - 9
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buffer = bytearray(self.bytes_per_frame) # use this if no CRC16 checksum is required
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buffer[:len(data_list[i])] = data_list[i] # set buffersize to length of data which will be send
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if self.mode >= 10: #generate CRC16 for modes 10-12..
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buffer = bytearray(self.payload_per_frame) # use this if CRC16 checksum is required ( DATA1-3)
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buffer[:len(data_list[i])] = data_list[i] # set buffersize to length of data which will be send
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crc = c_ushort(self.c_lib.freedv_gen_crc16(bytes(buffer), self.payload_per_frame)) # generate CRC16
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crc = crc.value.to_bytes(2, byteorder='big') # convert crc to 2 byte hex string
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buffer += crc # append crc16 to buffer
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#print(self.bytes_per_frame)
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#print(buffer)
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data = self.FrameBytes().from_buffer_copy(buffer) #change data format from bytearray to ctypes.u_byte
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self.c_lib.freedv_rawdatatx(self.freedv,mod_out,data) # modulate DATA and safe it into mod_out pointer
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sys.stdout.buffer.write(mod_out) # print data to terminal for piping the output to other programs
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sys.stdout.flush() # flushing stdout
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main() |