Digital Voice Dongle Project

This project is to create a small board that when plugged into a PC USB port, will provide an interface to a DVSI digital voice VOCODER chip.  The idea is to be able to use a PC and soundcard and listen and talk to a D-Star voice data stream over the internet.  Other uses would be to create a soundcard program that would implement the G4GUO HF digital voice modem or just to use as a low bit rate vocoder for VOIP.

First prototype:

General Specifications:

  • The PC interface is a standard USB serial COM port using an FTDI chip.  All communications with the dongle are via this serial port currently running at 230400 bps.
  • The dongle is powered from the USB port.
  • Current firmware simply sends and receives the entire AMBE 2000 compressed data frames and also the 16bit PCM audio data.
  • A bootloader is implemented so the firmware can be updated over the USB COM port.
  • The Atmel AT91SAM7S256 processor is used to allow lots of room for any custom applications to be downloaded.
  • A JTAG connector is available for debugging or for initial bootloader code programming.
  • A 4 pin serial connector is available that would allow connection of the dongle directly to an embedded processor. (would have to remove or not stuff the FTDI chip)
  • 4 LEDs indicate power, error, and serial port activity.
  • The PCB is designed to fit in an inexpensive Hammond 1551LTBU translucent blue case.
  • All the dongle firmware will be open source and compiled using free GCC toolsets.  FREERTOS is used for the operating system.  Eclipse can be used as an IDE for the tools.


DVDongle Technical Reference Manual:
dvdongletechref100.pdf (268K)

DVDongle Schematic:

DVDongle Rev 2 Schematic

DVDongle ARM Source Code(2 projects, one for bootloader and one for the application): (150K) (67K)

Here is a little utility used for updating the DVDongle application flash memory.  It takes a .hex file from the compiler and updates the DVDongle with it.  Currently there is no new updates available. (22K)

A windows test application to record/playback compressed audio was written to test out the hardware and also demo the voice compression modes. 

Here is the VC++6.0 source code and executable for AmbeTest program.  This was just a program used to test the DVDongle hardware so is not a slick user application.

Currently, the DVDongle is being sold by HRO. 

More user information can be found at:  DVDongle Official Home Page