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* AudioFilterFIR_F32
* Created: Chip Audette (OpenAudio) Feb 2017
* - Building from AudioFilterFIR from Teensy Audio Library (AudioFilterFIR credited to Pete (El Supremo))
#ifndef _filter_fir_f32_h
#define _filter_fir_f32_h
#include "Arduino.h"
#include "AudioStream_F32.h"
#include "arm_math.h"
// Indicates that the code should just pass through the audio
// without any filtering (as opposed to doing nothing at all)
#define FIR_F32_PASSTHRU ((const float32_t *) 1)
#define FIR_MAX_COEFFS 200
class AudioFilterFIR_F32 : public AudioStream_F32
//GUI: inputs:1, outputs:1 //this line used for automatic generation of GUI node
AudioFilterFIR_F32(void): AudioStream_F32(1,inputQueueArray),
coeff_p(FIR_F32_PASSTHRU), n_coeffs(1), configured_block_size(0) { }
AudioFilterFIR_F32(const AudioSettings_F32 &settings): AudioStream_F32(1,inputQueueArray),
coeff_p(FIR_F32_PASSTHRU), n_coeffs(1), configured_block_size(0) { }
//initialize the FIR filter by giving it the filter coefficients
void begin(const float32_t *cp, const int _n_coeffs) { begin(cp, _n_coeffs, AUDIO_BLOCK_SAMPLES); } //assume that the block size is the maximum
void begin(const float32_t *cp, const int _n_coeffs, const int block_size) { //or, you can provide it with the block size
coeff_p = cp;
n_coeffs = _n_coeffs;
// Initialize FIR instance (ARM DSP Math Library)
if (coeff_p && (coeff_p != FIR_F32_PASSTHRU) && n_coeffs <= FIR_MAX_COEFFS) {
arm_fir_init_f32(&fir_inst, n_coeffs, (float32_t *)coeff_p, &StateF32[0], block_size);
configured_block_size = block_size;
//Serial.print("AudioFilterFIR_F32: FIR is initialized. N_FIR = "); Serial.print(n_coeffs);
//Serial.print(", Block Size = "); Serial.println(block_size);
//} else {
// Serial.print("AudioFilterFIR_F32: *** ERROR ***: Cound not initialize. N_FIR = "); Serial.print(n_coeffs);
// Serial.print(", Block Size = "); Serial.println(block_size);
// coeff_p = NULL;
void end(void) { coeff_p = NULL; }
void update(void);
//void setBlockDC(void) {} //helper function that sets this up for a first-order HP filter at 20Hz
audio_block_f32_t *inputQueueArray[1];
// pointer to current coefficients or NULL or FIR_PASSTHRU
const float32_t *coeff_p;
int n_coeffs;
int configured_block_size;
// ARM DSP Math library filter instance
arm_fir_instance_f32 fir_inst;