mirror of
https://github.com/espressif/ESP8266_RTOS_SDK.git
synced 2025-06-04 20:53:06 +08:00
114 lines
3.8 KiB
C
114 lines
3.8 KiB
C
/* I2S Example
|
|
This example code will output 100Hz sine wave and triangle wave to 2-channel of I2S driver
|
|
Every 5 seconds, it will change bits_per_sample [16, 24, 32] for i2s data
|
|
This example code is in the Public Domain (or CC0 licensed, at your option.)
|
|
Unless required by applicable law or agreed to in writing, this
|
|
software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
|
|
CONDITIONS OF ANY KIND, either express or implied.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
#include "freertos/FreeRTOS.h"
|
|
#include "freertos/task.h"
|
|
#include "driver/i2s.h"
|
|
#include "esp_system.h"
|
|
#include "esp8266/pin_mux_register.h"
|
|
|
|
#define SAMPLE_RATE (36000)
|
|
#define I2S_NUM (0)
|
|
#define WAVE_FREQ_HZ (100)
|
|
#define PI (3.14159265)
|
|
#define I2S_MCLK_EN (1)
|
|
#define I2S_BCK_EN (1)
|
|
#define I2S_WS_EN (1)
|
|
#define I2S_DO_EN (1)
|
|
#define I2S_DI_EN (0)
|
|
|
|
#define SAMPLE_PER_CYCLE (SAMPLE_RATE/WAVE_FREQ_HZ)
|
|
|
|
static void setup_triangle_sine_waves(int bits)
|
|
{
|
|
int *samples_data = malloc(((bits + 8) / 16) * SAMPLE_PER_CYCLE * 4);
|
|
unsigned int i, sample_val;
|
|
double sin_float, triangle_float, triangle_step = (double) pow(2, bits) / SAMPLE_PER_CYCLE;
|
|
size_t i2s_bytes_write = 0;
|
|
|
|
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);
|
|
|
|
triangle_float = -(pow(2, bits) / 2 - 1);
|
|
|
|
for (i = 0; i < SAMPLE_PER_CYCLE; i++) {
|
|
sin_float = sin(i * PI / 180.0);
|
|
|
|
if (sin_float >= 0) {
|
|
triangle_float += triangle_step;
|
|
} else {
|
|
triangle_float -= triangle_step;
|
|
}
|
|
|
|
sin_float *= (pow(2, bits) / 2 - 1);
|
|
|
|
if (bits == 16) {
|
|
sample_val = 0;
|
|
sample_val += (short)triangle_float;
|
|
sample_val = sample_val << 16;
|
|
sample_val += (short) sin_float;
|
|
samples_data[i] = sample_val;
|
|
} else if (bits == 24) { //1-bytes unused
|
|
samples_data[i * 2] = ((int) triangle_float) << 8;
|
|
samples_data[i * 2 + 1] = ((int) sin_float) << 8;
|
|
} else {
|
|
samples_data[i * 2] = ((int) triangle_float);
|
|
samples_data[i * 2 + 1] = ((int) sin_float);
|
|
}
|
|
}
|
|
|
|
i2s_set_clk(I2S_NUM, SAMPLE_RATE, bits, 2);
|
|
i2s_write(I2S_NUM, samples_data, ((bits + 8) / 16)*SAMPLE_PER_CYCLE * 4, &i2s_bytes_write, 100);
|
|
|
|
free(samples_data);
|
|
}
|
|
|
|
void app_main()
|
|
{
|
|
// for 36Khz sample rates, we create 100Hz sine wave, every cycle need 36000/100 = 360 samples (4-bytes or 8-bytes each sample)
|
|
// depend on bits_per_sample
|
|
// using 6 buffers, we need 60-samples per buffer
|
|
// if 2-channels, 16-bit each channel, total buffer is 360*4 = 1440 bytes
|
|
// if 2-channels, 24-bit each channel, total buffer is 360*8 = 2880 bytes
|
|
i2s_config_t i2s_config = {
|
|
.mode = I2S_MODE_MASTER | I2S_MODE_TX, // Only TX
|
|
.sample_rate = SAMPLE_RATE,
|
|
.bits_per_sample = 16,
|
|
.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT, // 2-channels
|
|
.communication_format = I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB,
|
|
.dma_buf_count = 6,
|
|
.dma_buf_len = 256
|
|
};
|
|
i2s_pin_config_t pin_config = {
|
|
.bck_o_en = I2S_BCK_EN,
|
|
.ws_o_en = I2S_WS_EN,
|
|
.data_out_en = I2S_DO_EN,
|
|
.data_in_en = I2S_DI_EN
|
|
};
|
|
|
|
i2s_driver_install(I2S_NUM, &i2s_config, 0, NULL);
|
|
i2s_set_pin(I2S_NUM, &pin_config);
|
|
|
|
if (I2S_MCLK_EN) {
|
|
PIN_FUNC_SELECT(PERIPHS_IO_MUX_GPIO4_U, FUNC_CLK_XTAL);
|
|
}
|
|
|
|
int test_bits = 16;
|
|
|
|
while (1) {
|
|
setup_triangle_sine_waves(test_bits);
|
|
vTaskDelay(5000 / portTICK_RATE_MS);
|
|
test_bits += 8;
|
|
|
|
if (test_bits > 24) {
|
|
test_bits = 16;
|
|
}
|
|
}
|
|
} |