alex/esp-idf
alex/esp-idf
1
0
Fork 0
mirror of https://github.com/espressif/esp-idf.git synced 2024-10-05 20:47:46 -04:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity
f147a8d73d
esp-idf/examples/peripherals/i2s_adc_dac
History
Darian Leung 0c9e2c0fba esp_adc_cal/Remove lookup table 
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.
2018-02-22 20:01:41 +08:00
..
main esp_adc_cal/Remove lookup table 2018-02-22 20:01:41 +08:00
tools feature(I2S-ADC): add ADC mode for I2S. 2017-09-14 13:24:08 +08:00
Makefile feature(I2S-ADC): add ADC mode for I2S. 2017-09-14 13:24:08 +08:00
partitions_adc_dac_example.csv feature(I2S-ADC): add ADC mode for I2S. 2017-09-14 13:24:08 +08:00
README.md feature(I2S-ADC): add ADC mode for I2S. 2017-09-14 13:24:08 +08:00
sdkconfig.default feature(I2S-ADC): add ADC mode for I2S. 2017-09-14 13:24:08 +08:00

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:
    1. Erase flash
    2. Record audio from ADC and save in flash
    3. Read flash and replay the sound via DAC
    4. Play an example audio file(file format: 8bit/8khz/single channel)
    5. 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.