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119 lines
3.3 KiB
C++
119 lines
3.3 KiB
C++
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: kws.ino
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* Description: Very simple Yes detector
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*
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* $Date: 16 March 2022
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*
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* Target Processor: Cortex-M and Cortex-A cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2022 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <PDM.h>
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#include "arm_math.h"
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#include "coef.h"
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#include "scheduler.h"
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// default number of output channels
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static const char channels = 1;
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// default PCM output frequency
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static const int frequency = 16000;
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// Buffer to read samples into, each sample is 16-bits
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short sampleBuffer[AUDIOBUFFER_LENGTH];
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// Number of audio samples read
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volatile int samplesRead=0;
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void setup() {
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Serial.begin(9600);
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while (!Serial);
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Serial.println("Starting ...");
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// Configure the data receive callback
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PDM.onReceive(onPDMdata);
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// Optionally set the gain
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// Defaults to 20 on the BLE Sense and 24 on the Portenta Vision Shield
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// PDM.setGain(30);
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// Initialize PDM with:
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// - one channel (mono mode)
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// - a 16 kHz sample rate for the Arduino Nano 33 BLE Sense
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// - a 32 kHz or 64 kHz sample rate for the Arduino Portenta Vision Shield
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if (!PDM.begin(channels, frequency)) {
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Serial.println("Failed to start PDM!");
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while (1);
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}
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}
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void loop() {
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int error;
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uint32_t nb;
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// Start the CMSIS-DSP generated synchronous scheduling
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Serial.println("Scheduling ...");
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nb = scheduler(&error,window,coef_q15,coef_shift,intercept_q15,intercept_shift);
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Serial.println("End of scheduling");
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Serial.print("Error status = ");
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Serial.println(error);
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Serial.print("Nb iterations");
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Serial.println(nb);
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}
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/**
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* Callback function to process the data from the PDM microphone.
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* NOTE: This callback is executed as part of an ISR.
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* Therefore using `Serial` to print messages inside this function isn't supported.
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* */
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void onPDMdata() {
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// Query the number of available bytes
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int bytesAvailable = PDM.available();
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// Get free remaining bytes in the buffer
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// If real time is respected, there should never be
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// any overflow.
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int remainingFreeBytes = AUDIOBUFFER_LENGTH*2 - samplesRead*2;
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if (remainingFreeBytes >= bytesAvailable)
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{
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// Read into the sample buffer
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int nbReadBytes = PDM.read(sampleBuffer+samplesRead, bytesAvailable);
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// 16-bit, 2 bytes per sample
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samplesRead += nbReadBytes / 2;
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}
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else if (remainingFreeBytes > 0)
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{
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// Read into the sample buffer
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int nbReadBytes = PDM.read(sampleBuffer+samplesRead, remainingFreeBytes);
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// 16-bit, 2 bytes per sample
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samplesRead += nbReadBytes / 2;
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}
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}
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