kopia lustrzana https://github.com/espressif/esp-idf
![]() This commit removes the lookup table mode due to inferior performance when compared to linear mode under attenuation 0, 1 and 2. However small portions of the lookup table are kept for the higher voltages of atten 3 (above ADC reading 2880). That voltage range in atten 3 has non linear characteristics making the LUT performan better than linear mode. |
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.. | ||
main | ||
tools | ||
Makefile | ||
README.md | ||
partitions_adc_dac_example.csv | ||
sdkconfig.default |
README.md
I2S built-in ADC/DAC Example
- This is an example of:
- Recording sound from ADC
- Replay the recorded sound via DAC
- Play an audio file in flash
- Run this example
- Set partition table to "partitions_adc_dac_example.csv" in menuconfig, or rename sdkconfig.default to sdkconfig directly.
- Set IDF_PATH and run "make flash"
- This example will execute the following steps:
- Erase flash
- Record audio from ADC and save in flash
- Read flash and replay the sound via DAC
- Play an example audio file(file format: 8bit/8khz/single channel)
- Loop back to step 3
- Hardware connection:
ESP32 Microphone + amplifier amplifier + speaker GPIO36(ADC1CH0 input) data output pin GPIO25(DAC1 output) right channel speaker input GPIO26(DAC2 output) left channel speaker input
-
How to generate audio files:
- tools/generate_audio_file.py is an example of generate audio table from .wav files.
- In this example, the wav file must be in 16k/16bit mono format.
- generate_audio_file.py will bundle the wav files into a single table named audio_example_file.h
- Since the ADC can only play 8-bit data, the script will scale each 16-bit value to a 8-bit value.
- Since the ADC can only output positive value, the script will turn a signed value into an unsigned value.
- Note:
- DAC can only play 8-bit data, so the wav file data are scaled to 8-bit data.
- I2S DMA can only output 16-bit/32-bit data to DAC, DAC will only take the highest 8-bit data and output accordingly.
- Before I2S DMA can output data stream to DAC, the data format should be converted to 16-bit or 32-bit by padding zeros.