Here's the schematic diagram and the source code for the ERR Sound Converter board that was recently released by ERR. The code is released under the terms of the GNU General Public License, here's a clip from the header.
//****************************************************************************// © Copyright ElectricRR - 2013// This file is part of the OFST controller system.//// OFST is free software: you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// OFST is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with Foobar. If not, see <http://www.gnu.org/licenses/>.
I've compiled and loaded this code into the board using the current version of the Microchip MPLAB X IDE and free C compiler.
Enjoy.
