71 lines
1.9 KiB
Arduino
71 lines
1.9 KiB
Arduino
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#include <Arduino.h>
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#include "driver/i2s.h"
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#define I2S_PORT I2S_NUM_0
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#define SAMPLE_RATE 16000
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#define BUFFER_SIZE 256
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#define BLOCK_FRAMES 128 // 128 stereo frames = 512 bytes
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const uint16_t MAGIC = 0xABCD; // 2‑byte header marker
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void setup() {
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Serial.begin(1500000);
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i2s_config_t i2s_config = {
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.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
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.sample_rate = SAMPLE_RATE,
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.bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
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.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
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.communication_format = I2S_COMM_FORMAT_I2S,
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.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
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.dma_buf_count = 4,
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.dma_buf_len = BUFFER_SIZE,
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.use_apll = false,
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.tx_desc_auto_clear = false,
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.fixed_mclk = 0
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};
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i2s_pin_config_t pin_config = {
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.bck_io_num = 6,
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.ws_io_num = 7,
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.data_out_num = I2S_PIN_NO_CHANGE,
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.data_in_num = 8
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};
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i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
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i2s_set_pin(I2S_PORT, &pin_config);
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Serial.println("I2S microphone initialized!");
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}
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void loop() {
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int32_t buffer[BUFFER_SIZE];
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size_t bytes_read;
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// Collect one I2S DMA buffer
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i2s_read(I2S_PORT, (void*)buffer, sizeof(buffer), &bytes_read, portMAX_DELAY);
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int samples = bytes_read / 4; // 32-bit words
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static int16_t block[BLOCK_FRAMES * 2]; // stereo frames
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static int blockIndex = 0;
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for (int i = 0; i < samples; i += 2) {
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int32_t right32 = buffer[i];
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int32_t left32 = buffer[i + 1];
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int16_t right16 = (int16_t)(right32 >> 16);
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int16_t left16 = (int16_t)(left32 >> 16);
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block[blockIndex++] = left16;
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block[blockIndex++] = right16;
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if (blockIndex >= BLOCK_FRAMES * 2) {
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// Send header
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Serial.write((uint8_t*)&MAGIC, sizeof(MAGIC));
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// Send block
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Serial.write((uint8_t*)block, BLOCK_FRAMES * 4);
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blockIndex = 0;
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}
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}
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}
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