swgenerator.h

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/*
  Created by Fabrizio Di Vittorio (fdivitto2013@gmail.com) - <http://www.fabgl.com>
  Copyright (c) 2019-2022 Fabrizio Di Vittorio.
  All rights reserved.
 
 
* Please contact fdivitto2013@gmail.com if you need a commercial license.
 
 
* This library and related software is available under GPL v3.
 
  FabGL 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.
 
  FabGL 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 FabGL.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 
#pragma once
 
 
 
#include <stdint.h>
#include <stddef.h>
 
 
#if __has_include("esp32/rom/lldesc.h")
  #include "esp32/rom/lldesc.h"
#else
  #include "rom/lldesc.h"
#endif
 
#include "fabglconf.h"
 
 
 
 
 
namespace fabgl {
 
 
 
/*
 * This is a square wave generator or DMA->GPIO stream generator that uses APLL internal Audio PLL clock.
 *
 * When FABGLIB_USE_APLL_AB_COEF = 0 (the default) the frequency range is 2651514 Hz to 62500000 Hz.<br>
 * Average error is 21 Hz, Minimum error is 0, Maximum error is 1000 Hz except for range 41666667 Hz to 42708333 Hz while
 * frequency remains fixed at 41666666 Hz (error from 0 Hz to 1041666 Hz) and except for range 42708334 hz to 43748999 Hz while
 * frequency remains fixed at 43750000 Hz (error from 750001 Hz to 1041666 Hz).
 *
 * When FABGLIB_USE_APLL_AB_COEF = 1 the frequency range is 82500 Hz to 62500000 Hz. Unfortunately the output has lot of frequency jittering.<br>
 * Average error is about 7 Hz, Minimum error is 0, Maximum error is 6349 Hz.
 */
class GPIOStream {
 
public:
 
  void begin();
 
  /*
   * Initializes GPIOStream and associate GPIOs to the outputs.
   *
   * div1_onGPIO0 If true the undivided frequency is delivered on GPIO0.
   * div2 Specifies the GPIO where to send frequency / 2 (set GPIO_UNUSED to disable output).
   * div4 Specifies the GPIO where to send frequency / 4 (set GPIO_UNUSED to disable output).
   * div8 Specifies the GPIO where to send frequency / 8 (set GPIO_UNUSED to disable output).
   * div16 Specifies the GPIO where to send frequency / 16 (set GPIO_UNUSED to disable output).
   * div32 Specifies the GPIO where to send frequency / 32 (set GPIO_UNUSED to disable output).
   * div64 Specifies the GPIO where to send frequency / 64 (set GPIO_UNUSED to disable output).
   * div128 Specifies the GPIO where to send frequency / 128 (set GPIO_UNUSED to disable output).
   * div256 Specifies the GPIO where to send frequency / 256 (set GPIO_UNUSED to disable output).
   *
   * Example:
   *
   *     // Outputs 25Mhz on GPIO0 and 6.25Mhz on GPIO5, for 5 seconds
   *     GPIOStream.begin(true, GPIO_UNUSED, GPIO_NUM_5);
   *     GPIOStream.play(25000000);
   *     delay(5000);
   *     // Outputs 20Mhz on GPIO and 5Mhz on GPIO5, for 10 seconds
   *     GPIOStream.play(20000000);
   *     delay(10000);
   *     GPIOStream.stop();
   */
  void begin(bool div1_onGPIO0, gpio_num_t div2 = GPIO_UNUSED, gpio_num_t div4 = GPIO_UNUSED, gpio_num_t div8 = GPIO_UNUSED, gpio_num_t div16 = GPIO_UNUSED, gpio_num_t div32 = GPIO_UNUSED, gpio_num_t div64 = GPIO_UNUSED, gpio_num_t div128 = GPIO_UNUSED, gpio_num_t div256 = GPIO_UNUSED);
 
  /*
   * Disables all outputs.
   */
  void end();
 
  /*
   * Sets the main frequency.
   *
   * freq Frequency in Hertz.
   * dmaBuffers Use only to provide custom DMA buffers.
   *
   * Example:
   *
   *     // Set 25MHz as main frequency
   *     GPIOStream.play(25000000);
   */
  void play(int freq, lldesc_t volatile * dmaBuffers = nullptr);
 
  /*
   * Disables all outputs.
   */
  void stop();
 
private:
 
  void setupClock(int freq);
  static void setupGPIO(gpio_num_t gpio, int bit, gpio_mode_t mode);
 
  bool                m_DMAStarted;
  volatile lldesc_t * m_DMABuffer;
  volatile uint8_t *  m_DMAData;
};
 
 
 
 
 
} // end of namespace