mirror of
https://github.com/DJ2LS/FreeDATA
synced 2024-05-14 08:04:33 +00:00
81 lines
3.2 KiB
Python
81 lines
3.2 KiB
Python
#!/usr/bin/env python3
|
|
# -*- coding: utf-8 -*-
|
|
"""
|
|
Created on Sun Dec 13 13:45:58 2020
|
|
@author: DJ2LS
|
|
"""
|
|
|
|
import ctypes
|
|
from ctypes import *
|
|
import pathlib
|
|
|
|
import binascii #required for string.to_bytes() function
|
|
import sys
|
|
|
|
|
|
|
|
def main():
|
|
|
|
modem = FreeDV() #Load FreeDV Class as "modem"
|
|
|
|
data = b'HALLO' #byte string which will be send
|
|
|
|
modem.Modulate(data) #Call Modulate function, which modulates data and prints it to the terminal
|
|
|
|
|
|
class FreeDV():
|
|
|
|
def __init__(self):
|
|
|
|
self.mode = 12 # define mode
|
|
|
|
libname = pathlib.Path().absolute() / "libcodec2.so"
|
|
self.c_lib = ctypes.CDLL(libname) # Load FreeDV shared libary
|
|
|
|
self.freedv = self.c_lib.freedv_open(self.mode) #Set FreeDV waveform ( 10,11,12 --> DATAC1-3 )
|
|
|
|
self.bytes_per_frame = int(self.c_lib.freedv_get_bits_per_modem_frame(self.freedv)/8) #get bytes per frame from selected waveform
|
|
self.payload_per_frame = self.bytes_per_frame -2 #get frame payload because of 2byte CRC16 checksum
|
|
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
|
|
|
|
# MODULATION-OUT OBJECT
|
|
def ModulationOut(self):
|
|
return (c_short * self.n_tx_modem_samples) ##
|
|
|
|
# Pointer for changing buffer data type
|
|
def FrameBytes(self):
|
|
return (c_ubyte * self.bytes_per_frame)
|
|
|
|
# Modulate function which returns modulated data
|
|
def Modulate(self,data_out):
|
|
|
|
mod_out = self.ModulationOut()() # new modulation object and get pointer to it
|
|
|
|
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
|
|
data_list_length = len(data_list)
|
|
for i in range(data_list_length): # LOOP THROUGH DATA LIST
|
|
|
|
if self.mode < 10: # don't generate CRC16 for modes 0 - 9
|
|
|
|
buffer = bytearray(self.bytes_per_frame) # use this if no CRC16 checksum is required
|
|
buffer[:len(data_list[i])] = data_list[i] # set buffersize to length of data which will be send
|
|
|
|
if self.mode >= 10: #generate CRC16 for modes 10-12..
|
|
|
|
buffer = bytearray(self.payload_per_frame) # use this if CRC16 checksum is required ( DATA1-3)
|
|
buffer[:len(data_list[i])] = data_list[i] # set buffersize to length of data which will be send
|
|
|
|
crc = c_ushort(self.c_lib.freedv_gen_crc16(bytes(buffer), self.payload_per_frame)) # generate CRC16
|
|
crc = crc.value.to_bytes(2, byteorder='big') # convert crc to 2 byte hex string
|
|
buffer += crc # append crc16 to buffer
|
|
|
|
|
|
data = self.FrameBytes().from_buffer_copy(buffer) #change data format from bytearray to ctypes.u_byte and copy from buffer to data
|
|
|
|
self.c_lib.freedv_rawdatatx(self.freedv,mod_out,data) # modulate DATA and safe it into mod_out pointer
|
|
|
|
sys.stdout.buffer.write(mod_out) # print data to terminal for piping the output to other programs
|
|
sys.stdout.flush() # flushing stdout
|
|
|
|
|
|
main() |