15b4baba28
- minimize RAM usage of all components - use both IRAM and DRAM in player component so we can buffer up to 1s on modules without SPI RAM - support fragemented pcm chunks so we can use all available RAM if there isn't a big enough block available but still enough HEAP - reinclude all components from jorgen's master branch - add custom i2s driver to get a precise timing of initial sync - change wrong usage of esp_timer for latency measurement of snapcast protocol - add player component
115 lines
3.6 KiB
C
115 lines
3.6 KiB
C
// Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may 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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// http://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,
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// WITHOUT 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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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "esp_system.h"
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#include "driver/spi_master.h"
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#include "soc/gpio_struct.h"
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#include "driver/gpio.h"
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#include "driver/uart.h"
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#include "soc/uart_struct.h"
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#include <math.h>
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#include "esp_dsp.h"
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static const char *TAG = "main";
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// This example shows how to use FFT from esp-dsp library
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#define N_SAMPLES 2048 // Amount of real input samples
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int N = N_SAMPLES;
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// Input test array
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float x1[N_SAMPLES];
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float x2[N_SAMPLES];
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// Window coefficients
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float wind[N_SAMPLES];
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// Pointers to result arrays
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float* y1_cf = &x1[0];
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float* y2_cf = &x2[0];
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// diff of y1 and y2
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float diff_y[N_SAMPLES/2];
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void app_main()
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{
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esp_err_t ret;
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ESP_LOGI(TAG, "Start Example.");
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ret = dsps_fft2r_init_fc32(NULL, N>>1);
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if (ret != ESP_OK)
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{
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ESP_LOGE(TAG, "Not possible to initialize FFT2R. Error = %i", ret);
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return;
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}
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ret = dsps_fft4r_init_fc32(NULL, N >> 1);
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if (ret != ESP_OK)
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{
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ESP_LOGE(TAG, "Not possible to initialize FFT4R. Error = %i", ret);
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return;
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}
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// Generate hann window
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dsps_wind_hann_f32(wind, N);
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// Generate input signal for x1 A=1 , F=0.1
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dsps_tone_gen_f32(x1, N, 1.0, 0.16, 0);
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// Convert two input vectors to one complex vector
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for (int i=0 ; i< N ; i++)
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{
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x1[i] = x1[i] * wind[i];
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x2[i] = x1[i];
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}
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// FFT Radix-2
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unsigned int start_r2 = xthal_get_ccount();
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dsps_fft2r_fc32(x1, N>>1);
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// Bit reverse
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dsps_bit_rev2r_fc32(x1, N>>1);
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// Convert one complex vector with length N/2 to one real spectrum vector with length N/2
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dsps_cplx2real_fc32(x1, N>>1);
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unsigned int end_r2 = xthal_get_ccount();
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// FFT Radix-4
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unsigned int start_r4 = xthal_get_ccount();
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dsps_fft4r_fc32(x2, N>>1);
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// Bit reverse
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dsps_bit_rev4r_fc32(x2, N>>1);
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// Convert one complex vector with length N/2 to one real spectrum vector with length N/2
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dsps_cplx2real_fc32(x2, N>>1);
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unsigned int end_r4 = xthal_get_ccount();
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for (int i = 0 ; i < N/2 ; i++) {
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x1[i] = 10 * log10f((x1[i * 2 + 0] * x1[i * 2 + 0] + x1[i * 2 + 1] * x1[i * 2 + 1] + 0.0000001)/N);
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x2[i] = 10 * log10f((x2[i * 2 + 0] * x2[i * 2 + 0] + x2[i * 2 + 1] * x2[i * 2 + 1] + 0.0000001)/N);
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// Simple way to show two power spectrums as one plot
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diff_y[i] = fabs(x1[i] - x2[i]);
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}
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// Show power spectrum in 64x10 window from -100 to 0 dB from 0..N/4 samples
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ESP_LOGW(TAG, "Signal x1");
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dsps_view(x1, N/2, 64, 10, -60, 40, '|');
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ESP_LOGW(TAG, "Signal x2");
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dsps_view(x2, N/2, 64, 10, -60, 40, '|');
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ESP_LOGW(TAG, "Difference between signals x1 and x2 on one plot");
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dsps_view(diff_y, N/2, 64, 10, 0, 40, '-');
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ESP_LOGI(TAG, "FFT Radix 2 for %i complex points take %i cycles", N/2, end_r2 - start_r2);
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ESP_LOGI(TAG, "FFT Radix 4 for %i complex points take %i cycles", N/2, end_r4 - start_r4);
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ESP_LOGI(TAG, "End Example.");
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}
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