ADC/DAC software loopback demo

[中文]

1、Function overview

The main functions of the ADC/DAC software loopback demo of the AUDIO module are: transfer the audio data of the audio sampling (AUDIO_ADC) to the audio playback (AUDIO_DAC) through DMA for playback.

2、Code path

demo path: \components\demos\media\audio\aud

For the detailed description of the AUDIO ADC/DAC API interface, please refer to the same webpage: /api-reference/multi_media/bk_aud.html

3、Cli command introduction

The commands supported by the demo are as follows:

Command

Description

aud_adc_mcp_test {start|stop}

cpu transfers mic data to dac

aud_dtmf_mcp_test {start|stop}

cpu transfers dtmf data to dac

aud_adc_dma_test {start|stop}

DMA transfers mic data to dac

aud_adc_loop_test {start|stop}

mic data to dac hard loopback

aud_dtmf_loop_test {start|stop}

dtmf data to dac hard loopback

The macro configuration that the demo runs depends on:

Name

Description

File

value

CONFIG_AUDIO

Configure the audio function

\middleware\soc\bk7256_cp1\bk7256_cp1.defconfig

y

CONFIG_AUDIO_RISCV_IP_V1_0

Configure the audio function

\middleware\soc\bk7256_cp1\bk7256_cp1.defconfig

y

CONFIG_AUDIO_TEST

Configure the demo function

\middleware\soc\bk7256_cp1\bk7256_cp1.defconfig

y
Demo runs dependent libraries and drivers:

  • DMA DMA driver

  • AUD audio module driver

4、Demo introduction

The steps performed by the demo are as follows:

1.execute the test

  • Uart sends AT command cpu1 aud_adc_dma_test start to execute the test

2.Verification function

  • Connect the headset to hear the audio captured by the onboard mic

3.stop test

  • Uart sends AT command cpu1 aud_adc_dma_test stop to stop the test

Note

  • For other demos, you can start or stop the test by sending the corresponding commands according to the command table supported by the cli according to the above steps.

Execute the test command, the workflow of the case is shown in the following figure:

adc_to_dac_demo software flow

Figure 1. adc to dac demo flow chart

5、Detailed configuration and description

  • AUDIO_ADC performance

    AUDIO_ADC supports two working modes: DTMF and ADC:

    • DTMF working mode Direct digital mixing generates digital audio signal without mic sampling

    • ADC working mode ADC sampling of mic input signal, supports simultaneous sampling of up to 2 channels of mic

    The sampling rate Fs(bps) supported by AUDIO_ADC:

    • 8K

    • 16K

    • 44.1K

    • 48K

Important

  • 1.ADC working mode supports DMA transfer of mic sampling results

  • 2.DTMF working mode does not support DMA transfer of mixing results, only cpu transfer of mixing results

  • 3.ADC mode and DTMF mode only support one at the same time