163 lines
4.2 KiB
Markdown
163 lines
4.2 KiB
Markdown
# ESP32 Configuration
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If you are using ESP32 by Espressif Systems version 3.0.0 and later, audio tools will use the new adc_continuous API.
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For the adc_continuous API, audio tools provides the following options:
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- **sample_rate** (per channel), the effective ADC sampling rate is the number of channels x sample rate and can be:
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- ESP32: 20kHz to 2MHz
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- ESP32 S2, S3, H2, C6, C3: 611Hz to 83.333kHz
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for example:
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- 306
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- 4,000
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- 5,000
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- 8,000
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- 10,000
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- 11,025
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- 16,000
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- 20,000
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- 22,050
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- 40,000
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- 44,100
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- 48,000
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- 88,200
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- 96,000
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- 176,400
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- 192,200
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- 352,800
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- 384,000
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- 500,000
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- 1,000,000
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- **adc_bit_width**
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- 9, 10, 11, 12 depending on ESP32 model
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- audio stream is int16_t
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- **adc_calibration_active**: values measured are in mV
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- **is_auto_center_read**: subtraction of current estimated average from samples
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- **adc_attenuation**:
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| attenuation | range | accurate range |
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| ------------ | --------| -------------- |
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| ADC_ATTEN_DB_0 | 0..1.1V | 100-950mV |
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| ADC_ATTEN_DB_2_5| 0..1.5V | 100-1250mV |
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| ADC_ATTEN_DB_6 | 0..2.2V | 150-1750mV |
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| ADC_ATTEN_DB_12 | 0..3.9V | 150-2450mV |
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- **channels**:
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- mono = 1
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- stereo = 2
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- **adc_channels**: defining the channels (only channels on ADC unit 1 are supported) e.g.:
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- A3 on Sparkfun ESP32 Thing Plus is ADC_CHANNEL_3
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- A4 on Sparkfun ESP32 Thing Plus is ADC_CHANNEL_0
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- D5 on Adafruit ESP32-S3 is ADC_CHANNEL_4
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- D6 on Adafruit ESP32-S3 is ADC_CHANNEL_5
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- **buffer_size**
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- number of ADC conversion results per DMA frame, not the application processing block size
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- effective per-channel samples per frame are `buffer_size / channels`
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- maximum frame payload is 4092 bytes
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- practical maximum results per frame are `floor(4092 / SOC_ADC_DIGI_RESULT_BYTES)`
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- on ESP32 / ESP32-S2 the byte size is rounded up to a multiple of `SOC_ADC_DIGI_DATA_BYTES_PER_CONV`, so choose values that keep the aligned frame within 4092 bytes
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- minimum is number of channels
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- number needs to be divisible by number of channels
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- care must be taken because some streams in audio tools can not exceed 1024 bytes
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- **buffer_count**
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- number of DMA frames retained in the RX driver pool
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- increasing this adds tolerance for delayed reads but also increases RAM use
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## Example Configuration
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```
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auto adcConfig = adc.defaultConfig(RX_MODE);
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adcConfig.sample_rate = 44100;
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adcConfig.adc_bit_width = 12;
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adcConfig.adc_calibration_active = true;
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adcConfig.is_auto_center_read = false;
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adcConfig.adc_attenuation = ADC_ATTEN_DB_12;
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adcConfig.channels = 2;
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adcConfig.adc_channels[0] = ADC_CHANNEL_4;
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adcConfig.adc_channels[1] = ADC_CHANNEL_5;
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adcConfig.buffer_size = 512; // conversion results per DMA frame
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adcConfig.buffer_count = 4; // number of queued DMA frames in the RX pool
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```
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## ADC unit 1 channels on common ESP32 boards
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Audio tools continuous ADC framework supports ADC Unit 1 only.
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### Sparkfun ESP32 Thing Plus (ESP32)
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- A2, ADC1_CH6
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- A3, ADC1_CH3
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- A4, ADC1_CH0
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- 32, ADC1_CH4
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- 33, ADC1_CH5
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### Sparkfun ESP32 Thing Plus C (ESP32)
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- A2, ADC1_CH6
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- A3, ADC1_CH3
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- A4, ADC1_CH0
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- A5, ADC1_CH7
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- 32/6, ADC1_CH4
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- 33/10, ADC1_CH5
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### Sparkfun ESP32 Qwiic Pocket Development (ESP32C6)
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- 2, ADC1_CH2
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- 3, ADC1_CH3
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- 4, ADC1_CH4
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- 5, ADC1_CH5
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### ESP32-C6-DevKit
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- 4, ADC1_CH4
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- 5, ADC1_CH5
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- 6, ADC1_CH6
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- 7, ADC1_CH0
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- 0, ADC1_CH1
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- 2, ADC1_CH2
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- 3, ADC1_CH3
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### ESP32-H2-DevKit
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- 1, ADC1_CH0
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- 2, ADC1_CH1
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- 3, ADC1_CH2
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- 4, ADC1_CH3
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- 5, ADC1_CH4
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### ESP32-S3-DevKit
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- 1, ADC1_CH0
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- 2, ADC1_CH1
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- 4, ADC1_CH3
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- 5, ADC1_CH4
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- 6, ADC1_CH5
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- 7, ADC1_CH6
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- 8, ADC1_CH7
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- 3, ADC1_CH2
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- 9, ADC1_CH8
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- 10, ADC1_CH9
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### ESP32-C3-DevKit
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- 4, IO2, ADC1_CH2
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- 5, IO3, ADC1_CH3
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- 9, IO0, ADC1_CH0
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- 10, IO1, ADC1_CH1
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- 11, IO4, ADC1_CH4
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### Adafruit ESP32 Feather V2
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- D32, ADC1_CH4
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- D33, ADC1_CH5
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- A2, ADC1_CH6
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- A3, ADC1_CH3
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- A4, ADC1_CH0
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- D37, ADC1_CH1
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### Adafruit ESP32-S3 Feather
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- D5, ADC1_CH4
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- D6, ADC1_CH5
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- D9, ADC1_CH8
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- D10, ADC1_CH9
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- A5, ADC1_CH7
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### Adafruit QT Py ESP32-C3
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- A0, ADC1-CH4
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- A1, ADC1-CH3
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- A2, ADC1-CH1
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- A3, ADC1-CH0
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