mirror of
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166 lines
7.5 KiB
Markdown
166 lines
7.5 KiB
Markdown
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| Supported Targets | ESP32 | ESP32-C3 | ESP32-S3 |
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| ----------------- | ----- | -------- | -------- |
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# I2S Basic Standard Mode Example
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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This example is going to show how to use the PDM TX and RX mode.
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## How to Use Example
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### Hardware Required
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#### General
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* A development board with any one of ESP32, ESP32-C3 or ESP32-S3 SoC
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* A USB cable for power supply and programming
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#### PDM RX
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* A PDM microphone whose `sel` pin is supposed to be pulled down, and connecting its `clk` pin to `GPIO_NUM_4`, `data` pin to `GPIO_NUM_5`.
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```
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┌─────────────┐ ┌──────────────────┐
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│ ESP │ │ PDM microphone │
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│ │ PDM clock │ │
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│ GPIO 0 ├──────────────►│ CLK │
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│ │ PDM data │ │
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│ GPIO 2 │◄──────────────┤ DATA │
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│ │ │ │
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│ │ ┌─────┤ SEL │
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│ │ │ │ │
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│ GND ├─────────┴─────┤ GND │
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│ │ │ │
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│ VCC ├───────────────┤ VCC │
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└─────────────┘ └──────────────────┘
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```
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#### PDM TX
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* An earphone or a speaker
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* An audio power amplifier that can input PDM signal. If the power amplifier can only receive the analog signal without PDM clock, a band-pass filter is required to restore the PDM data wave into analog signal, before it is transmitted to the power amplifier.
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**MAX98358**
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```
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┌─────────────┐ ┌───────────────┐
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│ ESP │ │ MAX 98358 │
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│ │ PDM clock │ │
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│ GPIO 4 ├──────────────►│ CLK │ ┌─────────┐
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│ │ PDM data │ │ │ Speaker │
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│ GPIO 5 ├──────────────►│ DATA OUTP ├───┤ │
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│ │ │ │ │ │
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│ │ ┌─────┤ SD_MODE OUTN ├───┤ │
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│ │ │ │ │ │ │
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│ VCC ├─────────┴─────┤ VCC │ └─────────┘
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│ │ │ │
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│ GND ├───────────────┤ GND │
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└─────────────┘ └───────────────┘
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```
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**NS4150**
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```
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┌─────────────┐ ┌───────────────┐
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│ ESP │ │ NS 4150 │
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│ │ │ │
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│ GPIO 4 │ │ INN │ ┌─────────┐
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│ │PDM data┌────────────────┐ │ │ │ Speaker │
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│ GPIO 5 ├────────┤Band-pass Filter├───►│ INP VoP ├───┤ │
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│ │ └────────────────┘ │ │ │ │
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│ │ ┌───┤ CTRL VoN ├───┤ │
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│ │ │ │ │ │ │
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│ VCC ├──────────────────────────┴───┤ VCC │ └─────────┘
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│ │ │ │
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│ GND ├──────────────────────────────┤ GND │
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└─────────────┘ └───────────────┘
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```
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### Configure the Project
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PDM can only works in simplex mode, setting the macro `EXAMPLE_PDM_DIR` to `EXAMPLE_PDM_TX` or `EXAMPLE_PDM_RX` can choose the PDM direction of this example. But currently ESP32-C3 does not support PDM RX mode.
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### Build and Flash
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Build the project and flash it to the board, then run monitor tool to view serial output:
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```
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idf.py -p PORT build flash monitor
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```
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(To exit the serial monitor, type ``Ctrl-]``.)
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See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
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## Example Output
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### PDM TX
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While `EXAMPLE_PDM_DIR` is set to `EXAMPLE_PDM_TX`, then you can see the following log:
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```
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I2S PDM TX example start
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---------------------------
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D (284) i2s_common: tx channel is registered on I2S0 successfully
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D (294) i2s_common: DMA malloc info: dma_desc_num = 6, dma_desc_buf_size = dma_frame_num * slot_num * data_bit_width = 500
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D (304) i2s_pdm: Clock division info: [sclk] 160000000 Hz [mdiv] 3 [mclk] 49152000 Hz [bdiv] 8 [bclk] 6144000 Hz
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D (314) i2s_pdm: The tx channel on I2S0 has been initialized to PDM TX mode successfully
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D (324) i2s_common: i2s tx channel enabled
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Playing bass `twinkle twinkle little star`
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Playing alto `twinkle twinkle little star`
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Playing treble `twinkle twinkle little star`
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...
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```
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You can hear the audio 'twinkle twinkle little star' in three tones if you connected a speaker.on it.
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### PDM RX
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While `EXAMPLE_PDM_DIR` is set to `EXAMPLE_PDM_RX`, but without connecting a PDM microphone, then you can see the following log:
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```
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I2S PDM RX example start
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---------------------------
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D (10) i2s_common: rx channel is registered on I2S0 successfully
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D (10) i2s_common: DMA malloc info: dma_desc_num = 6, dma_desc_buf_size = dma_frame_num * slot_num * data_bit_width = 500
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D (20) i2s_common: i2s rx channel enabled
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Read Task: i2s read 2048 bytes
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-----------------------------------
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[0] -6595 [1] 0 [2] -29199 [3] -32768
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[4] -30203 [5] -32156 [6] -30704 [7] -31348
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Read Task: i2s read 2048 bytes
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-----------------------------------
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[0] -30935 [1] -30935 [2] -30935 [3] -30935
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[4] -30935 [5] -30935 [6] -30935 [7] -30935
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Read Task: i2s read 2048 bytes
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-----------------------------------
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[0] -30935 [1] -30935 [2] -30935 [3] -30935
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[4] -30935 [5] -30935 [6] -30935 [7] -30935
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```
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And only if you connect a PDM microphone, you can see the data is change:
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```
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I2S PDM RX example start
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---------------------------
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D (10) i2s_common: rx channel is registered on I2S0 successfully
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D (10) i2s_common: DMA malloc info: dma_desc_num = 6, dma_desc_buf_size = dma_frame_num * slot_num * data_bit_width = 500
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D (20) i2s_common: i2s rx channel enabled
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Read Task: i2s read 2048 bytes
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-----------------------------------
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[0] -3181 [1] 0 [2] -7194 [3] -24288
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[4] -777 [5] 3650 [6] 109 [7] 571
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Read Task: i2s read 2048 bytes
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-----------------------------------
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[0] 2391 [1] 2378 [2] 2397 [3] 2385
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[4] 2399 [5] 2375 [6] 2401 [7] 2389
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```
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## Troubleshooting
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For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you soon.
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