INMP441 bit per sample problem

[khanhbkisp]

Hi everyone. I'm working with INMP441 and ESP32 Dev kit v1 in ESP-IDF 4.4.3. I set i2s 32 bit per sample and then using i2s_read function to read data from DMA and store in an array. I copy exactly what this guy do https://esp32.com/viewtopic.php?t=15185

Code: [Select all] [Expand/Collapse]

1. // Connections to INMP441 I2S microphone
2. #define I2S_WS 25
3. #define I2S_SD 33
4. #define I2S_SCK 32
5.  
6. // Use I2S Processor 0
7. #define I2S_PORT I2S_NUM_0
8.  
9. #define bufferCount 8
10. #define bufferLen 64
11.  
12. int16_t buffer16[bufferLen] = {0};
13. uint8_t buffer32[bufferLen * 4] = {0};
14.  
15. // Set up I2S Processor configuration
16. void i2s_install() {
17.   // Set up I2S Processor configuration
18.   i2s_config_t i2s_config = {
19.     .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
20.     .sample_rate = 4000, // or 44100 if you like
21.     .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
22.     .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT, // Ground the L/R pin on the INMP441.
23.     .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_STAND_I2S),
24.     .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
25.     .dma_buf_count = bufferCount,
26.     .dma_buf_len = bufferLen,
27.     .use_apll = false,
28.     .tx_desc_auto_clear = false,
29.     .fixed_mclk = 0,
30.   };
31.  
32.   i2s_driver_install(I2S_PORT, &i2s_config, 0, NULL);
33. }
34.  
35. // Set I2S pin configuration
36. void i2s_setpin() {
37.     const i2s_pin_config_t pin_config = {
38.         .bck_io_num = I2S_SCK,
39.         .ws_io_num = I2S_WS,
40.         .data_out_num = -1,
41.         .data_in_num = I2S_SD
42.     };
43.  
44.     i2s_set_pin(I2S_PORT, &pin_config);
45. }

GeSHi © Codebox Plus Extension

The problem is after i2s_read funtion, my array value is zero. Below is how I read:

Code: [Select all] [Expand/Collapse]

1. while (1)
2.     {
3.         vTaskDelay(1); // Feed for watchdog, if not watchdog timer will be triggered!
4.  
5.         i2s_read(I2S_PORT, &buffer32, sizeof(buffer32), &bytesRead, 100);
6.         int samplesRead = bytesRead / 4;
7.  
8.         for (uint8_t i = 0; i < samplesRead; i++) {
9.             uint8_t mid = buffer32[i * 4 + 2];
10.             uint8_t msb = buffer32[i * 4 + 3];
11.             uint16_t raw = (((uint32_t)msb) << 8) + ((uint32_t)mid);
12.             memcpy(&buffer16[i], &raw, sizeof(raw)); // Copy so sign bits aren't interfered with somehow.
13.             printf("%d %d %d\n", 3000, -3000, buffer16[i]);
14.         }
15.     }

GeSHi © Codebox Plus Extension

I changed to 16 bit per sample and it works. But I want 32 bit per sample. My code is totally fine when I use arduino (I'm using arduino 2.0.1).
Please help me to find the solution for this problem.

[khanhbkisp]

Update: I switched to esp-idf 5.1 and it worked quite well. Maybe idf 4.4.3 has problem with reading 32-bit samples with INMP441 ?