/* sigma_delta.h - esp8266 sigma-delta source Copyright (c) 2014 Ivan Grokhotkov. All rights reserved. This file is part of the esp8266 core for Arduino environment. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /* /****************************************************************************** * Info Sigma delta module This module controls the esp8266 internal sigma delta source Each pin can be connected to the sigma delta source The target duty and frequency can be modified via the register GPIO_SIGMA_DELTA THE TARGET FREQUENCY IS DEFINED AS: FREQ = 80,000,000/prescaler * target /256 HZ, 0