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  1. /* Audio Library for Teensy 3.X
  2. * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
  3. *
  4. * Development of this audio library was funded by PJRC.COM, LLC by sales of
  5. * Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
  6. * open source software by purchasing Teensy or other PJRC products.
  7. *
  8. * Permission is hereby granted, free of charge, to any person obtaining a copy
  9. * of this software and associated documentation files (the "Software"), to deal
  10. * in the Software without restriction, including without limitation the rights
  11. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12. * copies of the Software, and to permit persons to whom the Software is
  13. * furnished to do so, subject to the following conditions:
  14. *
  15. * The above copyright notice, development funding notice, and this permission
  16. * notice shall be included in all copies or substantial portions of the Software.
  17. *
  18. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24. * THE SOFTWARE.
  25. */
  26. #ifndef synth_pinknoise_h_
  27. #define synth_pinknoise_h_
  28. #include "Arduino.h"
  29. #include "AudioStream.h"
  30. #include "utility/dspinst.h"
  31. class AudioSynthNoisePink : public AudioStream
  32. {
  33. public:
  34. AudioSynthNoisePink() : AudioStream(0, NULL) {
  35. plfsr = 0x5EED41F5 + instance_cnt++;
  36. paccu = 0;
  37. pncnt = 0;
  38. pinc = 0x0CCC;
  39. pdec = 0x0CCC;
  40. }
  41. void amplitude(float n) {
  42. if (n < 0.0) n = 0.0;
  43. else if (n > 1.0) n = 1.0;
  44. level = (int32_t)(n * 65536.0);
  45. }
  46. virtual void update(void);
  47. private:
  48. static const uint8_t pnmask[256];
  49. static const int32_t pfira[64];
  50. static const int32_t pfirb[64];
  51. static int16_t instance_cnt;
  52. int32_t plfsr; // linear feedback shift register
  53. int32_t pinc; // increment for all noise sources (bits)
  54. int32_t pdec; // decrement for all noise sources
  55. int32_t paccu; // accumulator
  56. uint8_t pncnt; // overflowing counter as index to pnmask[]
  57. int32_t level; // 0=off, 65536=max
  58. };
  59. #endif