I2S demo

[Chinese]

1、Function overview

The I2S demo supports the transmission of audio signals under different I2S configurations.

2、Code path

demo path: \components\demos\media\audio\i2s

For the detailed description of the API interface of the I2S module, please refer to the same webpage: /api-reference/multi_media/bk_i2s.html

3、Cli command introduction

The commands supported by the demo are as follows:

Command

Description

cpu1 i2s_master_test {start|stop}

Run the I2S test demo as master

cpu1 i2s_slave_test {start|stop}

Run the I2S test demo as a slave

The macro configuration that the demo runs depends on:

Name

Description

File

value

CONFIG_I2S

Configure I2S function enable

\properties\soc\bk7256_cp1\bk7256_cp1.defconfig

y

CONFIG_I2S_TEST

Configure demo enable

\properties\soc\bk7256_cp1\bk7256_cp1.defconfig

y
Demo runs dependent libraries and drivers:

  • GPIO GPIO driver

4、Demo introduction

The steps performed by the demo are as follows:

1.Connect two test boards

  • Test with two development boards, as the master and as the slave

  • Interconnect the GPIO6 and GPIO7 pins of the two boards

  • Connect GPIO8 on the master side to GPIO9 on the slave side

  • Connect GPIO9 on the master side to GPIO8 on the slave side

2.Start slave test

  • The slave side Uart sends the AT command cpu1 i2s_slave_test start to execute the I2S function test of the slave role

3.Start the master test

  • Uart sends AT command cpu1 i2s_master_test start to execute the I2S function test of the master role

4.stop test

  • Observe the serial port log printing. After the test is completed, the slave and master ends respectively send AT commands cpu1 i2s_slave_test stop and cpu1 i2s_master_test stop to stop the execution of the I2S function test.

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

i2s software flow

Figure 1. i2s work flow chart

5、Detailed configuration and description

The working modes and sampling rates supported by I2S are described as follows:

  • Work mode

    The I2S module supports the following multiple working modes:

    • Philips

    • Left Justified

    • Right Justified

    • Short Sync Frame

    • Long Sync Frame

    • Normal 2B+D

    • Delay 2B+D

    • TDM

Important

When using TDM mode, you only need to configure the working mode as one of the other 7 working modes, and then enable multiple channels. The module will combine the data of multiple channels into time-division multiplexing and send it out.

  • Sampling Rate

    The I2S module supports the following sampling rates Fs (bps):

    • 8K

    • 12K

    • 16K

    • 24K

    • 32K

    • 48K

    • 96K

    • 8.0182K

    • 11.025K

    • 22.05K

    • 44.1K

    • 88.2K

Note

The first 6 commonly used sampling rates are recommended

Important

Precautions:

  • 1.During I2S communication, the DIN and DOUT pins of the master and the slave should be connected correctly, the DIN of the master should be connected to the DOUT of the slave, and the DOUT of the master should be connected to the DIN of the slave;

  • 2.The working mode of master and slave should be consistent;

  • 3.The test demo mainly tests the first three working modes and different sampling rates.