mirror of
https://github.com/espressif/esp-idf.git
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132 lines
4.5 KiB
C
132 lines
4.5 KiB
C
/*
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* SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Unlicense OR CC0-1.0
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*/
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/* I2S Example
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* This example code will output 100Hz sine wave and triangle wave to 2-channel of I2S driver
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* Every 5 seconds, it will change bits_per_sample [16, 24, 32] for i2s data
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*/
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#include <stdio.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "driver/i2s_controller.h"
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#include "driver/gpio.h"
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#include "esp_system.h"
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#include "esp_log.h"
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#include <math.h>
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#define SAMPLE_RATE (36000)
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#define I2S_NUM (0)
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#define WAVE_FREQ_HZ (100)
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#define PI (3.14159265)
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#define I2S_BCK_IO (GPIO_NUM_4)
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#define I2S_WS_IO (GPIO_NUM_5)
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#define I2S_DO_IO (GPIO_NUM_18)
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#define I2S_DI_IO (-1)
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#define SAMPLE_PER_CYCLE (SAMPLE_RATE/WAVE_FREQ_HZ)
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static const char *TAG = "i2s_example";
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static i2s_chan_handle_t tx_handle = NULL;
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static void setup_triangle_sine_waves(int bits)
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{
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int *samples_data = malloc(((bits + 8) / 16) * SAMPLE_PER_CYCLE * 4);
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unsigned int i, sample_val;
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double sin_float, triangle_float, triangle_step = (double) pow(2, bits) / SAMPLE_PER_CYCLE;
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size_t i2s_bytes_write = 0;
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static i2s_std_slot_config_t slot_cfg = I2S_STD_PHILIP_SLOT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO);
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static i2s_std_clk_config_t clk_cfg = I2S_STD_CLK_CONFIG(SAMPLE_RATE);
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printf("\r\nTest bits=%d free mem=%d, written data=%d\n", bits, esp_get_free_heap_size(), ((bits + 8) / 16)*SAMPLE_PER_CYCLE * 4);
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triangle_float = -(pow(2, bits) / 2 - 1);
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for (i = 0; i < SAMPLE_PER_CYCLE; i++) {
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sin_float = sin(i * 2 * PI / SAMPLE_PER_CYCLE);
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if (sin_float >= 0) {
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triangle_float += triangle_step;
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} else {
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triangle_float -= triangle_step;
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}
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sin_float *= (pow(2, bits) / 2 - 1);
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if (bits == 16) {
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sample_val = 0;
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sample_val += (short)triangle_float;
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sample_val = sample_val << 16;
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sample_val += (short) sin_float;
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samples_data[i] = sample_val;
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} else if (bits == 24) { //1-bytes unused
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samples_data[i * 2] = ((int) triangle_float) << 8;
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samples_data[i * 2 + 1] = ((int) sin_float) << 8;
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} else {
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samples_data[i * 2] = ((int) triangle_float);
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samples_data[i * 2 + 1] = ((int) sin_float);
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}
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}
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ESP_LOGI(TAG, "set data bit width to %d", bits);
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/* Updata clock and slot information */
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slot_cfg.data_bit_width = bits;
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i2s_stop_channel(tx_handle);
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i2s_set_slot(tx_handle, &slot_cfg);
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if (bits == 24) {
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/**
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* Because '24' has factor '3'
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* The mclk multiple must be able to divide by '3' as well
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* Otherwise the sample rate won't be accurate */
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clk_cfg.mclk_multiple = I2S_MCLK_MULTIPLE_384;
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i2s_set_clock(tx_handle, &clk_cfg);
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} else {
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clk_cfg.mclk_multiple = I2S_MCLK_MULTIPLE_256;
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i2s_set_clock(tx_handle, &clk_cfg);
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}
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i2s_start_channel(tx_handle);
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ESP_LOGI(TAG, "write data");
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i2s_write_channel(tx_handle, samples_data, ((bits + 8) / 16)*SAMPLE_PER_CYCLE * 4, &i2s_bytes_write, 100);
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free(samples_data);
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}
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void app_main(void)
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{
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//for 36Khz sample rates, we create 100Hz sine wave, every cycle need 36000/100 = 360 samples (4-bytes or 8-bytes each sample)
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//depend on bits_per_sample
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//using 6 buffers, we need 60-samples per buffer
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//if 2-channels, 16-bit each channel, total buffer is 360*4 = 1440 bytes
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//if 2-channels, 24/32-bit each channel, total buffer is 360*8 = 2880 bytes
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i2s_gpio_config_t i2s_pin = {
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.mclk = I2S_GPIO_UNUSED,
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.bclk = I2S_BCK_IO,
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.ws = I2S_WS_IO,
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.dout = I2S_DO_IO,
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.din = I2S_DI_IO
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};
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i2s_chan_config_t chan_cfg = I2S_CHANNEL_CONFIG(I2S_ROLE_MASTER, I2S_COMM_MODE_STD, &i2s_pin);
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chan_cfg.id = I2S_NUM;
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i2s_new_channel(&chan_cfg, &tx_handle, NULL);
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i2s_std_slot_config_t slot_cfg = I2S_STD_PHILIP_SLOT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO);
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i2s_std_clk_config_t clk_cfg = I2S_STD_CLK_CONFIG(SAMPLE_RATE);
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#if SOC_I2S_SUPPORTS_APLL
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// APLL clock is more accurate when sample rate is high
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clk_cfg.clk_src = I2S_CLK_APLL;
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#endif
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i2s_init_channel(tx_handle, &clk_cfg, &slot_cfg);
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i2s_start_channel(tx_handle);
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int test_bits = 16;
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while (1) {
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setup_triangle_sine_waves(test_bits);
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vTaskDelay(pdMS_TO_TICKS(5000));
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test_bits += 8;
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if (test_bits > 32) {
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test_bits = 16;
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}
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}
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}
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