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99 lines
3.6 KiB
99 lines
3.6 KiB
/* |
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* This file is free software: you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License as published by the |
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* Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This file is distributed in the hope that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
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* See the GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License along |
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* with this program. If not, see <http://www.gnu.org/licenses/>. |
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* |
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* Code by Andy Piper and the betaflight team |
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*/ |
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#pragma once |
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#include <AP_HAL/AP_HAL.h> |
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#include "AP_HAL_ChibiOS_Namespace.h" |
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#if HAL_WITH_DSP |
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#include <arm_math.h> |
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#define DEBUG_FFT 0 |
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// ChibiOS implementation of FFT analysis to run on STM32 processors |
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class ChibiOS::DSP : public AP_HAL::DSP { |
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public: |
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// initialise an FFT instance |
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virtual FFTWindowState* fft_init(uint16_t window_size, uint16_t sample_rate, uint8_t sliding_window_size) override; |
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// start an FFT analysis with an ObjectBuffer |
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virtual void fft_start(FFTWindowState* state, FloatBuffer& samples, uint16_t advance) override; |
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// perform remaining steps of an FFT analysis |
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virtual uint16_t fft_analyse(FFTWindowState* state, uint16_t start_bin, uint16_t end_bin, float noise_att_cutoff) override; |
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// STM32-based FFT state |
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class FFTWindowStateARM : public AP_HAL::DSP::FFTWindowState { |
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friend class ChibiOS::DSP; |
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public: |
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FFTWindowStateARM(uint16_t window_size, uint16_t sample_rate, uint8_t sliding_window_size); |
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virtual ~FFTWindowStateARM(); |
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private: |
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// underlying CMSIS data structure for FFT analysis |
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arm_rfft_fast_instance_f32 _fft_instance; |
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}; |
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protected: |
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void vector_max_float(const float* vin, uint16_t len, float* maxValue, uint16_t* maxIndex) const override { |
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uint32_t mindex; |
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arm_max_f32(vin, len, maxValue, &mindex); |
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*maxIndex = mindex; |
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} |
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void vector_scale_float(const float* vin, float scale, float* vout, uint16_t len) const override { |
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arm_scale_f32(vin, scale, vout, len); |
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} |
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float vector_mean_float(const float* vin, uint16_t len) const override { |
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float mean_value; |
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arm_mean_f32(vin, len, &mean_value); |
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return mean_value; |
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} |
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void vector_add_float(const float* vin1, const float* vin2, float* vout, uint16_t len) const override { |
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arm_add_f32(vin1, vin2, vout, len); |
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} |
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private: |
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// following are the six independent steps for calculating an FFT |
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void step_hanning(FFTWindowStateARM* fft, FloatBuffer& samples, uint16_t advance); |
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void step_arm_cfft_f32(FFTWindowStateARM* fft); |
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void step_bitreversal(FFTWindowStateARM* fft); |
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void step_stage_rfft_f32(FFTWindowStateARM* fft); |
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void step_arm_cmplx_mag_f32(FFTWindowStateARM* fft, uint16_t start_bin, uint16_t end_bin, float noise_att_cutoff); |
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uint16_t step_calc_frequencies_f32(FFTWindowStateARM* fft, uint16_t start_bin, uint16_t end_bin); |
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// candan's frequency interpolator |
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float calculate_candans_estimator(const FFTWindowStateARM* fft, uint16_t k) const; |
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#if DEBUG_FFT |
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class StepTimer { |
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public: |
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uint32_t _timer_total; |
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uint32_t _timer_avg; |
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uint8_t _time_ticks; |
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void time(uint32_t start); |
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}; |
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uint32_t _output_count; |
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StepTimer _hanning_timer; |
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StepTimer _arm_cfft_f32_timer; |
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StepTimer _bitreversal_timer; |
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StepTimer _stage_rfft_f32_timer; |
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StepTimer _arm_cmplx_mag_f32_timer; |
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StepTimer _step_calc_frequencies; |
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#endif |
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}; |
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#endif |