feature(i2s): add i2s driver

examples/peripherals/i2s/main/i2s_example_main.c

@@ -0,0 +1,114 @@
+/* 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 = 60
+    };
+    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;
+        }
+    }
+}