MI AO API

REVISION HISTORY¶

Revision No.	Description	Date
3.50	Initial release	12/04/2020
3.51	Audio new architecture	07/19/2021
	Added procfs introduction	08/25/2021
3.52	Added MI_AO_GetAttr	09/08/2021
	Modified version: Audio 3.0 Version starts from 3.50(3.0 to 3.49 are Audio 2.0 versions)	12/29/2021
3.53	Added Mochi info	02/17/2022
3.54	Added Maruko info	03/29/2022
	Modified config file format of MI_AO_OpenCfgFile	05/19/2022
	Added the tiny version description	04/12/2023

1. OVERVIEW¶

1.1. Module Description¶

Audio Output (AO) is mainly used to configure and enable Audio Output devices, write audio data, and adjust volume.

1.2. Audio Codec Block Diagram¶

1.2.1. Muffin series¶

Figure 1‑1: Muffin series chips

The audio codec of Muffin series chips has the following resources:

WDMA * 5
RDMA * 3
DMIC interface (support 4Chn DMIC signal) * 1
ADC (support 2Chn Amic/Linein) * 2
I2S-TDM RX * 4
I2S-TDM TX * 2
DAC (support 2Chn Lineout) * 2
SRC * 1
HDMI TX * 1

1.2.2. Mochi series¶

Figure 1‑2: Mochi series chips

The audio codec of Mochi series chips has the following resources:

WDMA * 3
RDMA * 2
DMIC interface (support 4Chn DMIC signal) * 1
ADC (support 2Chn Amic/Linein) * 2
I2S-TDM RX (16 slot) * 1
I2S-TDM TX (16 slot, but there are only two channels of valid data) * 1
DAC (support 2Chn Lineout) * 2
SRC * 1
HDMI TX * 1

1.2.3. Maruko series¶

Figure 1-3: Maruko series chips

The audio codec of Maruko series chips has the following resources:

WDMA * 1
RDMA * 1
DMIC interface (support 6Chn DMIC signal) * 1
ADC (support 2Chn Amic/Linein) * 2
I2S RX(2 slot) * 2
I2S TX(2 slot) * 1
DAC (support 2Chn Lineout) * 2
SRC * 1

1.3. Audio Codec¶

DMA

Direct Memory Access, DMA transfer copies data from one address space to another address space, and provides high-speed data transfer between peripherals and memory or between memory and memory. When the CPU initializes this transfer action, the transfer action itself is realized and completed by the DMA controller. The DMA transmission method does not require the CPU to directly control the transmission, and there is no interrupt processing method to retain the scene and restore the scene process. The hardware opens a channel for direct data transmission for RAM and IO devices, which greatly improves the efficiency of the CPU.
WDMA

Direct Memory Access Writer.
RDMA

Direct Memory Access Reader.
MUX

MUX is the multiplexer data selector. In the process of multiplexing data transmission, any circuit that can be multiplexed out according to needs. The Mux in front of WDMA selects multiple data sources for WDMA, which can support the selection of ½/4 data sources (the data sources can be the same or different). Each data source has two channels, that is, the selection of 2/4/8 channels data is written to DRAM by WDMA, which acts as a multiplexer. However, the Mux, which is close to the output peripheral interface (such as I2S TX/HDMI/DAC, etc.), realizes the function of selecting one.
DPGA

Digital Programmable Gain Amplifier, is a very versatile amplifier, and its amplification factor can be controlled by a program as needed.
DMIC

Digital Microphone Interface, audio codec only provides DMIC interface, not a complete DMIC. The DMIC interface provides the clock signal required for DMIC work, and receives the PDM signal from the DMIC.
ADC

Analog Digital Conversion, the electronic component that convert analog signals into digital signals.
I2S

Inter-IC Sound integrated circuit built-in audio bus, is a bus standard developed by Philips for audio data transmission between digital audio devices. Sigmastar's I2S bus only supports the standard I2S data format and the left-justified I2S data format. At the same time, it also supports TDM (Time-Division Multiplexing) technology, which interleaves different signals in different time periods and transmits them along the same channel, which can support 4/8 channel data transmission.
DAC

Digital Analog Conversion, the electronic component that convert digital signals into analog signals.
SRC

Sample Rate Convert.
HDMI

High Definition Multimedia Interface, AO output interface, is a fully digital video and sound transmission interface, which can transmit uncompressed audio and video signals.
Mixer

Mixer, hardware mixing, using the linear superposition averaging algorithm (if the volume of a certain channel of audio is particularly low, the volume of the entire mixing result will be lowered), and the output sampling rate can be set after mixing.

1.4. Audio Codec Difference Description¶

1.4.1. Muffin series¶

Muffin series chips have I2S RX * 4, but I2S RX C and I2S RX D have two modes, one is called share mode and the other is called slave mode. In share mode, I2S RX C and I2S RX A share I2S Clock (Wck and Bck), and I2S RX D and I2S RX B share I2S Clock (Wck and Bck). When both I2S RX A and I2S RX C need to be used at the same time The I2S parameters of the I2S must be completely consistent. The Codec that is connected to the I2S RX C needs to connect the I2S Clock pins (Wck and Bck) to the I2S Clock (Wck and Bck) of the I2S RX A, and the Data pin to the Data of the I2S RX C. Then, the hardware solution is shown in the figure below. Slave mode, I2S RX C and I2S RX D have independent clocks, but they can only be used as slaves. These two modes can be set by i2s-rx-mode under the dts sound node, 0 is slave mode, and 1 is share mode.

1.4.2. Mochi series¶

The audio codec of Mochi series chips has the following resources: WDMA * 3, RDMA * 2, DMIC interface (support 4Chn DMIC signal) * 1, ADC (support 2Chn Amic/Linein) * 2, I2S-TDM RX(16 slot) * 1, I2S-TDM TX(16 slot) * 1, DAC (support 2Chn Lineout) * 2, SRC * 1, HDMI TX * 1.

The Mochi series chip I2S supports a maximum of 16 slots, and the sampling rate is newly added to support 96K/192K. Note: In the usage scenario of I2S, the maximum I2S BCK cannot exceed 30MHz (eg: BCK=16bit * 16slots * 192K=49.152M or BCK=32bit * 16slots * 192K=98.304M, the usage of BCK > 30MHz is not supported).

It supports mixing of two AO devices, represented by Mixer in the Audio Codec block diagram. After mixing, you can set the output sampling rate to 8K/16K/32K/48K (not supported yet).Supports separate mixing of two physical channels, represented by Mixer in the Audio Codec block diagram, and the output sampling rate after mixing supports 8K/16K/32K/48K (not supported yet).

Note: ADC_AB_PRE in the Audio Codec block diagram of Mochi series chip represents the audio signal before DPGA, as shown in Figure 1-2.

1.4.3. Maruko series¶

Maruko series chips, although there are two sets of I2S RX, but two sets of I2S RX cannot be used at the same time. Here are two sets of I2S RX usage scenarios:

I2S RX:

External codec transmits non-I2S signals, which need to be adjusted to Wck and Bck, such as receiving PCM signals.
Need to synchronize with Dmic Share clock to achieve Dmic and I2S RX.
External codec works in master mode.

I2S TRX:

Need to use I2S TX.

The I2S RX is selected by using the i2s-pcm under the dts sound node. 1 is I2S RX and 0 is I2S TRX. In addition, whether I2S RX and Dmic share clock are configured through dmic-bck-share. 1 is the share clock, and 0 is the independent clock.

1.5. Keyword¶

Device (Audio ouput device)

AO device refers to the RDMA of the audio codec. Device is an abstraction of DMA in audio codec by audio3.0. RDMA in audio codec and AO Device have a one-to-one correspondence. For example, AO Device0 corresponds to RDMA1 in audio codec, AO Device1 corresponds to RDMA2 in audio codec, and so on. The data streams of audio3.0 are all connected in series with DMA as the center.

Audio3.0 also includes another type of Device, that is, AI devices directly send data streams to AO devices without DMA, such as (Amic→Lineout). This type of device is called a direct device, that is, Passthrough, and currently only supports MI_AUDIO_PASSTHROUGH_DEV_1.
Interface (Audio output peripherals)

AO Interface is an abstraction of audio ouput peripheral interfaces in audio codec, such as Speaker/I2S Codec/HDMI interfaces.
Attach

AO attach refers to attaching Interface to RDMA. For AO Device, Attach is to connect the output signal of RDMA to a specific Interface, so that the peripheral can output audio signals. AO Device supports dynamic Attach.

When the same AO Interface is attached to two AO Devices, the output of the AO Interface is the result of the output of the two AO Devices mixing (supported by Mochi series).

When the use scene contains Passthrough, you need to attach AI first, then attach AO, otherwise it will not work normally.

The following figure is the result of attaching I2S TX and DAC0/1 to RDMA1. After the signal output from RDMA1 is adjusted by DPGA for gain adjustment, it is divided into 3 branches to reach DAC0, DAC1 and I2S TX respectively. The Attach of Ao Device is setting the flow direction of these branches.
Detach

Disconnecting Interface with RDMA.
Echo

The Echo of AO refers to the reference data of AEC. It can be seen from the audio codec block diagram that the input of SRC is the signal output by RDMA and amplified by DPGA, and the output of SRC is the signal after re-sampling the input, which can be sent to WDMA through Multi Channel as the echo reference data of the AEC algorithm. .

For AI Device, Echo represents the output signal of SRC in the audio codec block diagram. For AO Device, Echo means to connect the output of AO Device to the input of SRC. The following figure shows a simple block diagram of the data flow of AI Device and AO Device using Echo at the same time. The application can obtain the aligned AEC far end and near end data.
Sound Mode

AO Sound Mode refers to the audio channels, such as mono and stereo.
Channel Mode (Channel output mode)

Support static setting and dynamic setting of Channel Mode. Currently Muffin series chips not support dynamic Channel Mode setting.

AO Channel Mode refers to the output mode of the RDMA channel. For AO Device, Channel Mode determines the corresponding relationship between the audio channel of the audio data and the left and right channels of the Interface output. The following illustrates the role of Channel Mode in conjunction with the diagram.
1. E_MI_AO_CHANNEL_MODE_STEREO
  
  Normal stereo mode.
2. E_MI_AO_CHANNEL_MODE_DOUBLE_MONO
  
  Double Mono mono, the left and right channel output the same mono data.
  
  Double Mono stereo, the left and right channel output left and right channel mixed data. (Muffin series chips not supported).
3. E_MI_AO_CHANNEL_MODE_DOUBLE_LEFT
  
  Double Left stereo, the left and right channel output left channel data (Muffin series chips not supported).
4. E_MI_AO_CHANNEL_MODE_DOUBLE_RIGHT
  
  Double Right stereo, the left and right channel output right channel data (Muffin series chips not supported).
5. E_MI_AO_CHANNEL_MODE_EXCHANGE
  
  Exchange stereo, the left and right channel output left and right channel exchange data.
6. E_MI_AO_CHANNEL_MODE_ONLY_LEFT
  
  Only Left mono, only the left channel output mono data.
  
  Only Left stereo, only the left channel output stereo data.
7. E_MI_AO_CHANNEL_MODE_ONLY_RIGHT
  
  Only Right mono, only the right channel output mono data.
  
  Only Right stereo, only the right channel output stereo data.
Gain

AO Gain is divided into two categories in the audio3.0 architecture, one is the DPGA Gain associated with the Device, that is, the DPGA in the audio codec block diagram, and the other is the Gain unique to Interface. For AO, gain can only be adjusted through Dpga at present.
Format

What data format is used to represent an audio sample. Currently, only S16_LE format (PCM Linear 16bit (Little Endian)) is supported.
Sample Rate

Sample Rate, that is, the playback sample rate.
Period Size

For AO Device, Period Size represents the default starting condition of AO Device (only when the number of samples in the buffer is greater than the Period Size, the device will start).
I2S parameter
1. I2S Mode
  
  I2S Mode determines the working mode of I2S, whether it is standard I2S mode or Tdm I2S mode (2Channel or multi-channel), Master or Slave (Master provides synchronous clock, Slave receives synchronous clock). Generally speaking, there are no restrictions on the working mode, as long as it can match the external Codec clock.
2. I2S BitWidth
  
  The bit width of I2S sending and receiving data, currently support 16/32bit, but the hardware can only process 16bit, which means that when the bit width is 32bit, the lower 16bit is invalid data.
3. I2S Format
  
  I2S Format is the alignment of I2S. Currently, only I2S Philips and Left-justified alignment are supported. The following figure shows the waveforms of these two formats.
  
  I2S Philips alignment format, the first data bit of the sample data appears after the first BCLK (serial clock) of the WCLK (left and right channel switching clock) transition. In the left-aligned format, the first data bit of the sample data appears in the first BCLK (serial clock) of the WCLK (left and right channel switching clock) transition, and the polarity of WCLK is opposite to the alignment format of I2S Philips.
4. I2S Sample Rate
  
  The sample frequency of I2S transmission and reception.
5. Mclk
  
  Mclk, called the master clock, also called the system clock (System Clock), is generally 256 or 384 times the sample rate. The function is to enable better synchronization between systems, but it is not necessary. Currently only 12.288M, 16.384M, 18.432M, 24.576M, 24M, 48M, etc. are supported.
6. bSyncClock/4-Wire/6-Wire Mode
  
  There are two wiring methods for SigmaStar's I2S. One is the 4-Wire mode, including RX_WCK, RX_BCK, RX_SDI, TX_SDO four wires. In this mode, TX does not have an independent clock, and all clocks are provided by RX. Therefore, in this mode, TX needs to rely on RX to use. TX cannot be used alone, and the parameters of I2S TX must be consistent with I2S RX. The other is 6-Wire mode, including RX_WCK, RX_BCK, RX_SDI, TX_WCK, TX_BCK, TX_SDO six wires. In this mode, RX and TX are independent and not related. The choice of 4-Wire/6-Wire Mode needs to be decided according to specific scenarios.
  
  If bSyncClock in the MI API I2S parameter is TRUE, 4-Wire Mode is used, and FALSE is 6-Wire Mode. The RX and TX belonging to the same group of I2S cannot be set to 4-Wire Mode on one side and 6-Wire Mode on the other side.
7. Slot
  
  Slot represents the number of channels transmitted by I2S. Currently, 2 slots are supported in I2S mode, and 4/8/16 slots are supported in Tdm mode.
Passthrough

Passthrough refers to the channel that directly sends the data stream from the AI device to the AO device without DMA. Take ADC_AB→DAC_AB as an example, the red marked path in Figure 1-3 below:

Figure 1-3: Mochi series chip passthrough diagram

Muffin series chips only support Passthrough from ADC_AB as input device to DAC_AB as output device.

Mochi series chips support any combination passthrough from ADC_AB/DMIC_A_01/ DMIC_A_23/I2S_A_01/…/ I2S_A_EF as input device to DAC_AB/I2S_TX/HDMI as output device. The current Passthrough limitations of Mochi series chips are: only support 48K sampling rate; Passthrough Device does not support Channel Mode setting; in Passthrough + DMA mixing scenarios, the output device only supports DAC_AB.

2. API REFERENCE¶

Audio output (AO) is mainly used to enable audio output devices, send audio frames to output channels and other functions.

API name	Features
MI_AO_Open	Open audio output device
MI_AO_OpenWithCfgFile	Open the audio output device and initialize it according to the config file
MI_AO_Close	Close AO devices
MI_AO_AttachIf	Mount peripherals to AO device
MI_AO_DetachIf	Disconnect peripherals from audio output device
MI_AO_Write	Write audio data
MI_AO_Start	Start the AO device and start playing
MI_AO_Stop	Stop the AO device and stop playing
MI_AO_Pause	Pause AO device
MI_AO_Resume	Resume AO device
MI_AO_SetVolume	Set AO device volume
MI_AO_GetVolume	Get AO device volume
MI_AO_SetMute	Set AO device mute parameter
MI_AO_GetMute	Get AO device mute parameter
MI_AO_SetIfVolume	Set AO peripheral volume
MI_AO_GetIfVolume	Get AO peripheral volume
MI_AO_SetIfMute	Set AO peripheral mute parameter
MI_AO_GetIfMute	Get AO peripheral mute parameter
MI_AO_SetI2SConfig	Set I2S TX config info
MI_AO_GetI2SConfig	Get I2S TX config info
MI_AO_AdjustSpeed	Adjust the playback speed of AO device
MI_AO_GetTimestamp	Get the current playback timestamp and cached data volume of the AO device
MI_AO_GetLatency	Get the delay of AO device
MI_AO_InitDev	Initialize AO device
MI_AO_DeinitDev	De-Initialize AO device
MI_AO_GetAttr	Get AO device attributes
MI_AO_SetChannelMode	Dynamically set the channel output mode (Muffin series chips not support)

2.1. MI_AO_Open¶

Features

Open audio output device.

Syntax

MI_S32 MI_AO_Open (MI_AUDIO_DEV AoDevId, const MI_AO_Attr_t *pstAttr);

Parameters

parameter name description Input/Output

AoDevId AO device number Input

pstAttr AO device attribute pointer Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note

Audio output device attributes include data format, sound mode, sampling rate, Playback threshold, and channel output mode.
- Audio data format(MI_AUDIO_Format_e)
  
  The data format of the sampled samples. Only S16_LE is supported.
- Audio sound mode(MI_AUDIO_SoundMode_e)
  
  Channels of the data to be played, such as mono/stereo.
- Audio sampling rate(MI_AUDIO_SampleRate_e)
  
  Number of samples in one second, the higher the sampling rate, the smaller the distortion, but the amount of data processed also increases.
  
  The 8k sampling rate is used for voice, and the 32k or higher sampling rate is used for audio.
- Playback threshold (u32PeriodSize)
  
  Only when the data cache meets this sample will it start playing. After this parameter is set, it is recommended to write audio data in this size. When the period size is 0, APP needs to actively call MI_AO_Start to start playing.
- Channel output mode (MI_AO_ChannelMode_e)
  
  It determines the output mode of the audio data in the audio device.
- The behavior of Maruko series chip I2S TX is not affected by the MI_AO_ChannelMode_e parameter.

Example

A simple example is as follow:

1.  MI_AO_Attr_t stAoSetAttr;  
2.  memset(&stAoSetAttr, 0x0, sizeof(MI_AO_Attr_t));  
3.  stAoSetAttr.enFormat = E_MI_AUDIO_FORMAT_PCM_S16_LE;  
4.  stAoSetAttr.enSoundMode = E_MI_AUDIO_SOUND_MODE_MONO;  
5.  stAoSetAttr.enSampleRate = E_MI_AUDIO_SAMPLE_RATE_8000;  
6.  stAoSetAttr.u32PeriodSize = 1024;  
7.  stAoSetAttr.enChannelMode = E_MI_AO_CHANNEL_MODE_DOUBLE_MONO;  
8.  ExecFunc(MI_AO_Open(AoDevId, &stAoSetAttr), MI_SUCCESS);

The detailed example is as follow:

1.  MI_AUDIO_DEV AoDevId = 0;    
2.  MI_AO_Attr_t stAoSetAttr, stAoGetAttr;    
3.  MI_S8 s8LeftVolume, s8RightVolume;      
4.  MI_AO_GainFading_e eGainFading;      
5.      
6.  memset(&stAoSetAttr, 0x0, sizeof(MI_AO_Attr_t));    
7.      
8.  // Set the Format of AO Device to S16_LE    
9.  stAoSetAttr.enFormat = E_MI_AUDIO_FORMAT_PCM_S16_LE;    
10.     
11. // Set the Sound Mode of AO Device to Mono    
12. stAoSetAttr.enSoundMode = E_MI_AUDIO_SOUND_MODE_MONO;    
13.     
14. // Set the sample rate of AO Device to 8KHz    
15. stAoSetAttr.enSampleRate = E_MI_AUDIO_SAMPLE_RATE_8000;    
16.     
17. // Set the starting condition of AO Device to 1024 sampling samples    
18. stAoSetAttr.u32PeriodSize = 1024;    
19.     
20. // Set the Channel Mode of AO Device to Double Mono    
21. stAoSetAttr.enChannelMode = E_MI_AO_CHANNEL_MODE_DOUBLE_MONO;    
22.     
23. // Open AO Device    
24. ExecFunc(MI_AO_Open(AoDevId, &stAoSetAttr), MI_SUCCESS);    
25.   
26. // Get AO Device attributes    
27. ExecFunc(MI_AO_GetAttr(AoDevId, &stAoGetAttr), MI_SUCCESS);    
28.     
29. // Attach DAC_AB to AO Device    
30. ExecFunc(MI_AO_AttachIf(AoDevId, E_MI_AO_IF_DAC_AB, 0), MI_SUCCESS);   
31. 
32. // Dynamically set the audio channel mode to Only-Left  
33. ExecFunc(MI_AO_SetChannelMode(AoDevId, E_MI_AO_CHANNEL_MODE_ONLY_LEFT), MI_SUCCESS);
34.      
35. // Set Dpga Gain    
36. s8LeftVolume = 0;      
37. s8RightVolume = 0;      
38. eGainFading = E_MI_AO_GAIN_FADING_OFF;    
39. ExecFunc(MI_AO_SetVolume(AoDevId, s8LeftVolume, s8RightVolume, eGainFading), MI_SUCCESS);    
40.     
41. // Write data to AO Device   
42. MI_AO_Write(AoDevId, u8TempBuf, s32ReadSize, 0, -1);    
43.     
44. // Detach DAC_AB    
45. ExecFunc(MI_AO_DetachIf(AoDevId, E_MI_AO_IF_DAC_AB), MI_SUCCESS);     
46.     
47. // Close AO Device    
48. ExecFunc(MI_AO_Close(MI_AO_DEV_1), MI_SUCCESS);

2.2. MI_AO_OpenWithCfgFile¶

Features

Open the audio output device and initialize it according to the config file.

Syntax

MI_S32 MI_AO_OpenWithCfgFiile(MI_AUDIO_DEV AoDevId, const char *pCfgPath);

Parameters

parameter name description Input/Output

AoDevId AO device number Input

pCfgPath Path of config file Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- This interface is equivalent to the combination of MI_AO_Open and MI_AO_AttachIf.
- If the audio output device is enabled, it returns success.
- The config file template is as follow:
```
1.  {
2.      "DEV":{
3.          "enFormat":0,
4.          "enSoundMode":2,
5.          "enSampleRate":8000,
6.          "u32PeriodSize":1024,
7.          "enChannelMode":0,
8.          "enAoIfs":[1,4]
9.      },
10.     "I2S_A":{
11.         "enMode":0,
12.         "enBitWidth":0,
13.         "enFormat":0,
14.         "enSampleRate":8000,
15.         "enMclk":0,
16.         "bSyncClock":0,
17.         "u32TdmSlots":2
18.     }
19. }
```
  The “DEV” node contains parameters required by MI_AO_Open and MI_AO_AttachIf. “enFormat”, “enSoundMode”, “enSampleRate”, “u32PeriodSize”, and “enChannelMode” are the configuration information required by MI_AO_Open, please refer to the description of MI_AO_Attr_t. “enAoIfs” is the configuration information required by MI_AO_AttachIf, please refer to MI_AO_If_e for details. The “I2S_A” node contains configuration information required by MI_AO_SetI2SConfig, please refer to MI_AUDIO_I2sConfig_t for details.
  
  In the above configuration information, enFormat = 0 means AO Device adopts S16_LE format, enSoundMode = 1 means Sound Mode adopts Mono, enSampleRate = 8000 means AO Device uses 8KHz sampling frequency, u32PeriodSize = 1024 means that the starting condition is 1024 sampling points, enChannelMode = 1 means Double Mono, enAoIfs=1 means attach DAC0/1 to RDMA. If you need to use I2S TX, you also need to set the parameters of I2S TX. The above configuration works on I2S_A, enMode = 0 means using I2S Master mode, enBitWidth = 0 means I2S receiving bit width is 16bit, enFormat = 0 means aligning according to I2S Philips mode, enSampleRate = 8000 means that the sampling frequency of I2S RX is 8KHz, enMclk = 0 means that Mclk is not used, bSyncClock = 0 means 4-wire mode, and u32TdmSlots means receiving 2-channel data.
  
  AO template.json
- The tiny version does not support this API.

Example

1.  char *path = "/tmp/Dev0Cfg.json";  
2.  ExecFunc(MI_AO_OpenWithCfgFile(AoDevId, path), MI_SUCCESS);

2.3. MI_AO_Close¶

Features

Close AO devices.

Syntax

MI_S32 MI_AO_Close (MI_AUDIO_DEV AoDevId);

Parameters

parameter name description Input/Output

AoDevId AO device number Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- If the AO device is already closed, it will return Success directly.
Example

A simple example is as follow:
```
1. ExecFunc(MI_AI_Close(MI_AI_DEV_1), MI_SUCCESS);
```
For detailed examples, please refer to MI_AO_Open.

2.4. MI_AO_AttachIf¶

Features

Mount peripherals to AO device.

Syntax

MI_S32 MI_AO_AttachIf (MI_AUDIO_DEV AoDevId, MI_AO_If_e enAoIfs, MI_U32 u32AudioDelay);

Parameters

parameter name	description	Input/Output
AoDevId	AO device number	Input
enAoIfs	AO Interface, the peripheral information that needs to be mounted to the AO device, you can use "	" to indicate that multiple peripherals are mounted
u32AudioDelay	Delay parameters(reserved)	Input

Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- This interface can only be called after MI_AI_Open succeeds.
- If you need to mount the I2S TX to the AO device, please call MI_AI_SetI2SConfig first to initialize the I2S TX.
- If you want to obtain echo reference data, attach E_MI_AO_IF_ECHO_A to AO module and attach E_MI_AI_IF_ECHO_A to AI module.

Example

1. ExecFunc(MI_AO_AttachIf(AoDevId, E_MI_AO_IF_DAC_AB, 0), MI_SUCCESS);

2.5. MI_AO_DetachIf¶

Features

Disconnect peripherals from audio output device.

Syntax

MI_S32 MI_AO_DetachIf (MI_AUDIO_DEV AoDevId, MI_AO_If_e enAoIfs);

Parameters

parameter name	description	Input/Output
AoDevId	AO device number	Input
enAoIfs	AO Interface, the peripheral information that needs to be unmounted to the AO device, you can use "\|" to indicate that multiple peripherals are mounted	Input

Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_AttachIf succeeds.
- The I2S TX and ECHO of Maruko series chips do not support Detach.
Example

A simple example is as follow:
```
1. ExecFunc(MI_AO_DetachIf(AoDevId, E_MI_AO_IF_DAC_AB), MI_SUCCESS);
```
For detailed examples, please refer to MI_AO_Open.

2.6. MI_AO_Write¶

Features

Write audio data.

Syntax

MI_S32 MI_AO_Write (MI_AUDIO_DEV AoDevId, const void *pvBuffer, MI_U32 u32Bytes, MI_U64 u64Pts, MI_S32 s32TimeoutMs);

Parameters

parameter name	description	Input/Output
AoDevId	AO device number	Input
pvBuffer	Audio data pointer	Input
u32Bytes	Audio data length	Input
u64Pts	Audio data timestamp (reserved)	Input
s32TimeoutMs	Timeout for writing audio data. -1: blocking mode, waiting for no data; 0 means non-blocking mode, when there is no data, it will return an error; >0: blocking s32TimeoutMs milliseconds, and it will report an error and return when it times out.	Input

Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- This interface can only be called after MI_AI_Open and MI_AI_AttachIf succeed.
- s32TimeoutMs must be greater than or equal to -1, when it is equal to -1, use blocking mode to write data, when it is equal to 0, use non-blocking mode to write data, when it is greater than 0, after blocking s32MilliSec for milliseconds, it will return a timeout and report an error.

Example

A simple example is as follow:

1.  MI_U8 u8TempBuf[1024] = {0};  
2.  MI_S32 s32ReadSize;  
3.  s32ReadSize = read(s32Fd, pu8TempBuf, sizeof(u8TempBuf));  
4.  if (s32ReadSize > 0)  
5.  {  
6.      MI_AO_Write(AoDevId, u8TempBuf, s32ReadSize, 0, -1);  
7.  }

For detailed examples, please refer to MI_AO_Open.

2.7. MI_AO_Start¶

Features

Start the AO device and start playing.

Syntax

MI_S32 MI_AO_Start (MI_AUDIO_DEV AoDevId);

Parameters

parameter name description Input/Output

AoDevId AO device number Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.
- When this interface is called, even if the playback threshold < u32PeriodSize, it can be played immediately.

Example

1. ExecFunc(MI_AO_Start(AoDevId),MI_SUCCESS);

2.8. MI_AO_Stop¶

Features

Stop the AO device and stop playing.

Syntax

MI_S32 MI_AO_Stop (MI_AUDIO_DEV AoDevId);

Parameters

parameter name description Input/Output

AoDevId AO device number Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.
- When the interface is called, the playback stops immediately, and the original cached data will also be lost.

Example

1. ExecFunc(MI_AO_Stop(AoDevId),MI_SUCCESS);

2.9. MI_AO_Pause¶

Features

Pause AO device.

Syntax

MI_S32 MI_AO_Pause (MI_AUDIO_DEV AoDevId);

Parameters

parameter name description Input/Output

AoDevId AO device number Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.
- When the interface is called, the playback will be paused immediately

Example

1. ExecFunc(MI_AO_Pause(AoDevId),MI_SUCCESS);

2.10. MI_AO_Resume¶

Features

Resume AO device.

Syntax

MI_S32 MI_AO_Resume (MI_AUDIO_DEV AoDevId);

Parameters

parameter name description Input/Output

AoDevId AO device number Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Pause succeeds.
- When the interface is called, the playback will be resume immediately

Example

1. ExecFunc(MI_AO_Resume(AoDevId),MI_SUCCESS);

2.11. MI_AO_SetVolume¶

Features

Set AO device volume.

Syntax

MI_AO_SetVolume (MI_AUDIO_DEV AoDevId, MI_S8 s8LeftVolume, MI_S8 s8RightVolume, MI_AO_GainFading_e enFading);

Parameters

parameter name	description	Input/Output
AoDevId	AO device number	Input
s8LeftVolume	Left channel volume (-60 ~ 30dB, 1dB/step)	Input
s8RightVolume	Right channel volume (-60 ~ 30dB, 1dB/step)	Input
eFading	The changing speed of audio gain	Input

Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.

Example

1.  MI_S8 s8LeftVolume, s8RightVolume;  
2.  MI_AO_GainFading_e eGainFading;  
3.  s8LeftVolume = 0;  
4.  s8RightVolume = 0;  
5.  eGainFading = E_MI_AO_GAIN_FADING_OFF;  
6.  ExecFunc(MI_AO_SetVolume(AoDevId, s8LeftVolume, s8RightVolume, eGainFading), MI_SUCCESS);

2.12. MI_AO_GetVolume¶

Features

Get AO device volume.

Syntax

MI_S32 MI_AO_GetVolume (MI_AUDIO_DEV AoDevId, MI_S8 *ps8LeftVolume, MI_S8 *ps8RightVolume);

Parameters

parameter name description Input/Output

AoDevId AO device number Input

ps8LeftVolume Left channel volume pointer Output

ps8RightVolume Right channel volume pointer Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_SetVolume succeeds.

Example

1. MI_S8 s8LeftVolume, s8RightVolume;

2. ExecFunc(MI_AO_GetVolume(AoDevId, &s8LeftVolume, &s8RightVolume), MI_SUCCESS);

2.13. MI_AO_SetMute¶

Features

Set AO device mute parameter.

Syntax

MI_S32 MI_AO_SetMute (MI_AUDIO_DEV AoDevId, MI_BOOL bLeftMute, MI_BOOL bRightMute, MI_AO_GainFading_e enFading);

Parameters

parameter name	description	Input/Output
AoDevId	AO device number	Input
bLeftMute	Left channel mute parameter	Input
bRightMute	Right channel mute parameter	Input
eFading	The changing speed of audio gain (reserved)	Input

Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.
- When using MI_AO_SetVolume to adjust the volume, it will automatically exit the mute state.

Example

1. MI_BOOL bLeftMute = TRUE;

2. MI_BOOL bRightMute = TRUE;

3. MI_AO_GainFading_e eGainFading = E_MI_AO_GAIN_FADING_OFF;

4. ExecFunc(MI_AO_SetMute(AoDevId, bLeftMute, bRightMute, eGainFading), MI_SUCCESS);

2.14. MI_AO_GetMute¶

Features

Get AO device mute parameter.

Syntax

MI_S32 MI_AO_GetMute (MI_AUDIO_DEV AoDevId, MI_BOOL *pbLeftMute, MI_BOOL *pbRightMute);

Parameters

parameter name description Input/Output

AoDevId AO device number Input

pbLeftMute Left channel mute parameter pointer Output

pbRightMute Right channel mute parameter pointer Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- It can only be called after MI_AO_Open succeeds.

Example

1. MI_BOOL bLeftMute;

2. MI_BOOL bRightMute;

3. ExecFunc(MI_AO_GetMute(AoDevId, bLeftMute, bRightMute), MI_SUCCESS);

2.15. MI_AO_SetIfVolume¶

Features

Set AO peripheral volume.

Syntax

MI_S32 MI_AO_SetIfVolume (MI_AO_If_e enAoIf, MI_S8 s8LeftVolume, MI_S8 s8RightVolume);

Parameters

parameter name description Input/Output

enAoIf AO peripheral Input

s8LeftVolume Left channel volume Input

s8RightVolume Right channel volume Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so
Note
- No interface supports it.

Example

1. MI_S8 s8LeftVolume = 0;

2. MI_S8 s8RightVolume = 0;

3. ExecFunc(MI_AO_SetIfVolume(E_MI_AO_IF_DAC_AB, s8LeftVolume, s8RightVolume), MI_SUCCESS);

2.16. MI_AO_GetIfVolume¶

Features

Get AO peripheral volume.

Syntax

MI_S32 MI_AO_GetIfVolume (MI_AO_If_e enAoIf, MI_S8 *ps8LeftVolume, MI_S8 *ps8RightVolume);

Parameters

Parameter Name Description Input/Output

enAoIf AO peripheral Input

ps8LeftVolume Left channel volume pointer Output

ps8RightVolume Left channel volume pointer Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header: mi_ao.h
- Library: libmi_ao.a/libmi_ao.so
Note
- The tiny version does not support this API.

Example

1. MI_S8 s8LeftVolume = 0;

2. MI_S8 s8RightVolume = 0;

3. ExecFunc(MI_AO_GetIfVolume(E_MI_AO_IF_DAC_AB, &s8LeftVolume, &s8RightVolume), MI_SUCCESS);

2.17. MI_AO_SetIfMute¶

Features

Set AO peripheral mute parameter.

Syntax

MI_S32 MI_AO_SetIfMute (MI_AO_If_e enAoIf, MI_BOOL bLeftMute, MI_BOOL bRightMute);

Parameters

Parameter Name Description Input/Output

enAoIf AO peripheral Input

bLeftMute Left channel mute parameter Input

bRightMute Right channel mute parameter Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header: mi_ao.h
- Library: libmi_ao.a/libmi_ao.so
Note
- Currently only DAC_AB supports this interface.

Example

1. MI_BOOL bLeftMute = 0;

2. MI_BOOL bRightMute = 0;

3. ExecFunc(MI_AO_SetIfMute(E_MI_AO_IF_DAC_AB, bLeftMute, bRightMute), MI_SUCCESS);

2.18. MI_AO_GetIfMute¶

Features

Get AO peripheral mute parameter.

Syntax

MI_S32 MI_AO_GetIfMute (MI_AO_If_e enAoIf, MI_BOOL *pbLeftMute, MI_BOOL *pbRightMute);

Parameters

Parameter Name Description Input/Output

enAoIf AO peripheral Input

pbLeftMute Left channel mute parameter pointer Output

pbRightMute Right channel mute parameter pointer Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.a/libmi_ao.so

Example

1. MI_BOOL bLeftMute = 0;

2. MI_BOOL bRightMute = 0;

3. ExecFunc(MI_AO_GetIfMute(E_MI_AO_IF_DAC_AB, &s8LeftVolume, &s8RightVolume), MI_SUCCESS);

2.19. MI_AO_SetI2SConfig¶

Features

Set I2S TX config info.

Syntax

MI_S32 MI_AO_SetI2SConfig (MI_AO_If_e enAoI2SIf, const MI_AUDIO_I2sConfig_t *pstConfig);

Parameters

Parameter Name Description Input/Output

enAiI2Sif Audio I2S TX output peripheral Input

pstConfig Audio I2S TX config info Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- The enSampleRate in MI_AUDIO_I2sConfig_t must be the same as the enSampleRate in MI_AI_Attr_t, otherwise attach will report an error.
- When the same I2S TX interface is detached by all devices, that is, no device is attached to the I2S TX interface, the I2S TX parameters will be reset. If you need to attach to a device, you must first reset the I2S parameters.

Example

1.  MI_AUDIO_I2sConfig_t stAoI2sACfg;  
2.  memset(&stAoI2sACfg, 0x0, sizeof(stAoI2sACfg));  
3.  stAoI2sACfg.enMode = E_MI_AUDIO_I2S_MODE_I2S_MASTER;  
4.  stAoI2sACfg.enFormat = E_MI_AUDIO_I2S_FMT_I2S_MSB;  
5.  stAoI2sACfg.enSampleRate = E_MI_AUDIO_SAMPLE_RATE_8000;  
6.  stAoI2sACfg.enMclk = E_MI_AUDIO_I2S_MCLK_0;  
7.  stAoI2sACfg.bSyncClock = TRUE;  
8.  stAoI2sACfg.u32TdmSlots = 2;  
9.  stAoI2sACfg.enBitWidth = E_MI_AUDIO_BIT_WIDTH_16;  
10. ExecFunc(MI_AO_SetI2SConfig(E_MI_AO_IF_I2S_A, &stAoI2sACfg), MI_SUCCESS);

2.20. MI_AO_GetI2SConfig¶

Features

Get I2S TX config info.

Syntax

MI_S32 MI_AO_GetI2SConfig (MI_AO_If_e enAoI2SIf, MI_AUDIO_I2sConfig_t *pstConfig);

Parameters

Parameter Name Description Input/Output

enAiI2SIf Audio I2S TX output peripheral Input

pstConfig Audio I2S TX config info Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a

Example

1.  MI_AUDIO_I2sConfig_t stAoI2sACfg;  
2.  memset(&stAoI2sACfg, 0x0, sizeof(stAoI2sACfg));  
3.  ExecFunc(MI_AO_GetI2SConfig(E_MI_AO_IF_I2S_A, &stAoI2sACfg), MI_SUCCESS);

2.21. MI_AO_AdjustSpeed¶

Features

Adjust the playback speed of AO device.

Syntax

MI_S32 MI_AO_AdjustSpeed (MI_AUDIO_DEV AoDevId, MI_S32 s32Speed);

Parameters

Parameter Name Description Input/Output

AoDevId AO device number Input

s32Speed Sampling rate of playback Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- Not supported.

Example

1. ExecFunc(MI_AO_AdjustSpeed(AoDevId, 8000), MI_SUCCESS);

2.22. MI_AO_GetTimestamp¶

Features

Get the current playback timestamp and cached data volume of the AO device.

Syntax

MI_S32 MI_AO_GetTimestamp (MI_AUDIO_DEV AoDevId, MI_U32 *pu32Remaining, MI_U64 *pu64TStamp);

Parameters

Parameter Name Description Input/Output

AoDevId AO device number Input

pu32Remaining Current cached data Output

pu64TStamp Current playback timestamp (reserved) Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- This interface can only be called after MI_AO_Open succeeds.

Example

1. MI_U32 u32Remaining;

2. MI_U64 u64TStamp;

3. ExecFunc(MI_AO_GetTimestamp(AoDevId, &u32Remaining, &u64TStamp), MI_SUCCESS);

2.23. MI_AO_GetLatency¶

Features

Get the delay of AO device.

Syntax

MI_S32 MI_AO_GetLatency (MI_AUDIO_DEV AoDevId, MI_U32 *pu32Latency);

Parameters

Parameter Name Description Input/Output

AoDevId AO device number Input

pu32Latency Delay time (ms) Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- This interface can only be called after MI_AO_Open succeeds.
- The specific function of this interface has not been implemented yet.

Example

1. MI_U32 u32Latency;

2. ExecFunc(MI_AO_GetLatency(AoDevId, &u32Latency), MI_SUCCESS);

2.24. MI_AO_InitDev¶

Features

Initialize AO device.

Syntax

MI_S32 MI_AO_InitDev (MI_AO_InitParam_t *pstInitParam);

Parameters

Parameter Name Description Input/Output

pstInitParam Device initialization parameter Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- It must be used in pairs with MI_AO_DeinitDev, and cannot be called repeatedly, otherwise it returns to fail.
- Only used to reinitialize the AO module after the STR state is enabled.

2.25. MI_AO_DeInitDev¶

Features

De- Initialize AO device.
Syntax
```
MI_S32 MI_AO_DeInitDev (void);
```
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header files: mi_ao.h
- Library file: libmi_ao.so/libmi_ao.a
Note
- This function must be called after the device is initialized, otherwise, it returns to fail.
- If it is not called before the app exits, the device will be automatically deinitialized internally
- It must be used in pairs with MI_AO_InitDev, and cannot be called repeatedly, otherwise it returns to fail.

2.26. MI_AO_GetAttr¶

Features

Get audio output device attributes.

Syntax

MI_S32 MI_AO_GetAttr(MI_AUDIO_DEV AoDevId, MI_AO_Attr_t *pstAttr);

Parameters

Parameter Name Description Input/Output

AoDevId Audio output device ID Input

pstAttr Audio output device attributes Output
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header: mi_ao.h
- Library: libmi_ao.so/libmi_ao.a
Note
- This function must be called after opening the device successfully, otherwise it will return failed.

2.27. MI_AO_SetChannelMode¶

Features

Dynamically set the channel output mode.

Syntax

MI_S32 MI_AO_SetChannelMode(MI_AUDIO_DEV AoDevId, MI_AO_ChannelMode_e enChannelMode);

Parameters

Parameter Name Description Input/Output

AoDevId Audio output device ID Input

enChannelMode Channel output mode Input
Return Value
- Zero: Successful
- Non-zero: Failed, see error code for details
Requirement
- Header: mi_ao.h
- Library: libmi_ao.so/libmi_ao.a
Note
- This function can only be called after MI_AO_AttachIf succeeds.
- Only Mochi series chips support this setting.

Example

A simple example is as follows:

2.  ExecFunc(MI_AO_SetChannelMode(AoDevId, E_MI_AO_CHANNEL_MODE_ONLY_LEFT), MI_SUCCESS);

For detailed examples, please refer to MI_AO_Open.

3. AO DATA TYPE¶

The AO module related data types are defined as follows:

Data type	Definition
MI_AUDIO_DEV	Define the audio Input/Output device number
MI_AUDIO_Format_e	Define audio data format
MI_AUDIO_SoundMode_e	Define audio sound mode
MI_AUDIO_SampleRate_e	Define the audio sample rate
MI_AO_ChannelMode_e	Define the channel output mode of the audio device
MI_AO_Attr_t	Define AO device attribute structure
MI_AO_If_e	Define audio peripheral interface
MI_AO_GainFading_e	Define the changing speed of audio device gain
MI_AUDIO_I2sMode_e	Define the working mode of audio I2S TXRX/TX
MI_AUDIO_I2sBitWidth_e	Define audio I2S TXRX/TX bit width
MI_AUDIO_I2sFormat_e	Define the data transmission format of audio I2S RX/TX
MI_AUDIO_I2sMclk_e	Define the mclk frequency of audio I2S RX/TX
MI_AUDIO_I2sConfig_t	Define I2S RX/TX config info
MI_AO_InitParam_t	Audio output device initialization parameter

3.1. MI_AUDIO_DEV¶

Description

Define the audio Input/Output device number.
Definition
```
typedef MI_S32 MI_AUDIO_DEV
```

3.2. MI_AUDIO_Format_e¶

Description

Define audio data format.

Definition

typedef enum

{

    E_MI_AUDIO_FORMAT_INVALID = -1,

    E_MI_AUDIO_FORMAT_PCM_S16_LE = 0,

} MI_AUDIO_Format_e;

Member

Member name description

E_MI_AUDIO_FORMAT_INVALID Invalid data format

E_MI_AUDIO_FORMAT_PCM_S16_LE PCM Linear 16bit (Little Endian)
Related data types and interfaces

MI_AO_Attr_t

3.3. MI_AUDIO_SoundMode_e¶

Description

Define audio sound mode.

Definition

typedef enum

{

    E_MI_AUDIO_SOUND_MODE_MONO = 1,

    E_MI_AUDIO_SOUND_MODE_STEREO = 2,

    E_MI_AUDIO_SOUND_MODE_4CH = 4,

    E_MI_AUDIO_SOUND_MODE_6CH = 6,

    E_MI_AUDIO_SOUND_MODE_8CH = 8,

}MI_AUDIO_SoundMode_e

Member

Member name	description
E_MI_AUDIO_SOUND_MODE_MONO	MONO
E_MI_AUDIO_SOUND_MODE_STEREO	STEREO
E_MI_AUDIO_SOUND_MODE_4CH	4-channels; not supported
E_MI_AUDIO_SOUND_MODE_6CH	6-channels; not supported
E_MI_AUDIO_SOUND_MODE_8CH	8-channels; not supported

Related data types and interfaces

MI_AO_Attr_t

3.4. MI_AUDIO_SampleRate_e¶

Description

Define the audio sample rate.

Definition

typedef enum

{

    E_MI_AUDIO_SAMPLE_RATE_8000 = 8000,

    E_MI_AUDIO_SAMPLE_RATE_11052 = 11025,

    E_MI_AUDIO_SAMPLE_RATE_12000 = 12000,

    E_MI_AUDIO_SAMPLE_RATE_16000 = 16000,

    E_MI_AUDIO_SAMPLE_RATE_22050 = 22050,

    E_MI_AUDIO_SAMPLE_RATE_24000 = 24000,

    E_MI_AUDIO_SAMPLE_RATE_32000 = 32000,

    E_MI_AUDIO_SAMPLE_RATE_44100 = 44100,

    E_MI_AUDIO_SAMPLE_RATE_48000 = 48000,

    E_MI_AUDIO_SAMPLE_RATE_96000 = 96000,

    E_MI_AUDIO_SAMPLE_RATE_192000 = 192000,

}MI_AUDIO_SampleRate_e;

Member

Member name	description
E_MI_AUDIO_SAMPLE_RATE_8000	8kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_11025	11.025kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_12000	12kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_16000	16kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_22050	22.05kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_24000	24kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_32000	32kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_44100	44.1kHz sample rate
E_MI_AUDIO_SAMPLE_RATE_48000	48kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_96000	96kHz sampling rate
E_MI_AUDIO_SAMPLE_RATE_192000	192kHz sampling rate

Precautions
- Except I2S TX which supports 8/16/32/48/96/192kHz, and I2S TX can only be attached separately when using 96/192kHz, other AO peripherals only support 8/16/32/48kHz.
- Muffin's I2S RX only supports 8/16/32/48/96 kHz.
Related data types and interfaces

MI_AO_Attr_t

3.5. MI_AO_ChannelMode_e¶

Description

Define the channel output mode of the audio device.

Definition

typedef enum

{

    E_MI_AO_CHANNEL_MODE_STEREO,

    E_MI_AO_CHANNEL_MODE_DOUBLE_MONO,

    E_MI_AO_CHANNEL_MODE_DOUBLE_LEFT,

    E_MI_AO_CHANNEL_MODE_DOUBLE_RIGHT,

    E_MI_AO_CHANNEL_MODE_EXCHANGE,

    E_MI_AO_CHANNEL_MODE_ONLY_LEFT,

    E_MI_AO_CHANNEL_MODE_ONLY_RIGHT,

}MI_AO_ChannelMode_e;

Member

Member name	description
E_MI_AO_CHANNEL_MODE_STEREO	Stereo mode
E_MI_AO_CHANNEL_MODE_DOUBLE_MONO	Stereo: the left and right channels output mixed data Mono: the left and right channels output the same mono data
E_MI_AO_CHANNEL_MODE_DOUBLE_LEFT	Stereo: left and right channels output left channel data
E_MI_AO_CHANNEL_MODE_DOUBLE_RIGHT	Stereo: left and right channels output right channel data
E_MI_AO_CHANNEL_MODE_EXCHANGE	Stereo: the data output of the left and right channels are interchanged
E_MI_AO_CHANNEL_MODE_ONLY_LEFT	Stereo: the left channel output left channel data Mono: the left channel outputs mono data
E_MI_AO_CHANNEL_MODE_ONLY_RIGHT	Stereo: the right channel output is right channel data Mono: the right channel is output as mono data

Precautions
- Muffin don’t support E_MI_AO_CHANNEL_MODE_DOUBLE_MONO (stereo) / E_MI_AO_CHANNEL_MODE_DOUBLE_LEFT (stereo) / E_MI_AO_CHANNEL_MODE_DOUBLE_RIGHT (stereo).
Related data types and interfaces

MI_AO_Attr_t

3.6. MI_AO_Attr_t¶

Description

Define AO device attribute structure.

Definition

typedef struct MI_AO_Attr_s

{

    MI_AUDIO_Format_e enFormat;

    MI_AUDIO_SoundMode_e enSoundMode;

    MI_AUDIO_SampleRate_e enSampleRate;

    MI_U32 u32PeriodSize;

    MI_AO_ChannelMode enChannelMode;

    MI_AUDIO_SampleRate_e enMixerSampleRate;

}MI_AO_Attr_t;

Member

Member name	description
enFormat	Audio data format. Static attributes.
enSoundMode	Audio sound mode. Static attributes.
enSampleRate	Audio sampling rate. Static attributes.
u32PeriodSize	Playback threshold. Static attributes.
enChannelMode	Channel output mode. Static attributes.
enMixerSampleRate	Output sample rate after mixing. Static property, it only takes effect in the use scene of the mix, if this parameter is not set, the default is 48K, no need to set it in other scenes (not supported currently).

Related data types and interfaces

MI_AO_Open

3.7. MI_AO_If_e¶

Description

Define audio peripheral interface.

Definition

typedef enum
{
    E_MI_AO_IF_NONE = 0x0u,
    E_MI_AO_IF_DAC_AB = 0x1u,
    E_MI_AO_IF_DAC_CD = 0x02u,
    E_MI_AO_IF_I2S_A = 0x4u,
    E_MI_AO_IF_I2S_B = 0x8u,
    E_MI_AO_IF_ECHO_A = 0x10u,
    E_MI_AO_IF_HDMI_A = 0x20u,
    E_MI_AO_IF_MAX,
} MI_AO_If_e;

Member

Member name	description
E_MI_AO_IF_NONE	None
E_MI_AO_IF_DAC_AB	DAC0/1
E_MI_AO_IF_DAC_CD	DAC⅔
E_MI_AO_IF_I2S_A	I2S TX A
E_MI_AO_IF_I2S_B	I2S RX B
E_MI_AO_IF_ECHO_A	SRC data(echo)
E_MI_AO_IF_HDMI_A	HDMI TX

Related data types and interfaces

MI_AO_AttachIf

MI_AO_DetachIf

MI_AO_SetIfVolume

MI_AO_GetIfVolume

MI_AO_SetIfMute

MI_AO_GetIfMute

MI_AO_SetI2SConfig

MI_AO_GetI2SConfig

3.8. MI_AO_GainFading_e¶

Description

Define the changing speed of audio device gain.

Definition

typedef enum{

    E_MI_AO_GAIN_FADING_OFF = 0,

    E_MI_AO_GAIN_FADING_1_SAMPLE,

    E_MI_AO_GAIN_FADING_2_SAMPLE,

    E_MI_AO_GAIN_FADING_4_SAMPLE,

    E_MI_AO_GAIN_FADING_8_SAMPLE,

    E_MI_AO_GAIN_FADING_16_SAMPLE,

    E_MI_AO_GAIN_FADING_32_SAMPLE,

    E_MI_AO_GAIN_FADING_64_SAMPLE,

}MI_AO_GainFading_e;

Member

Member name	description
E_MI_AO_GAIN_FADING_OFF	Disable Fading function, set gain takes effect immediately
E_MI_AO_GAIN_FADING_1_SAMPLE	Enable Fading function, 1 sample point change 0.5dB
E_MI_AO_GAIN_FADING_2_SAMPLE	Enable Fading function, 2 sample points change 0.5dB
E_MI_AO_GAIN_FADING_4_SAMPLE	Enable Fading function, 4 sample points change 0.5dB
E_MI_AO_GAIN_FADING_8_SAMPLE	Enable Fading function, 8 sample points change 0.5dB
E_MI_AO_GAIN_FADING_16_SAMPLE	Enable Fading function, 16 sample points change 0.5dB
E_MI_AO_GAIN_FADING_32_SAMPLE	Enable Fading function, 32 sample points change 0.5dB
E_MI_AO_GAIN_FADING_64_SAMPLE	Enable Fading function, 64 sample points change 0.5dB

Related data types and interfaces

MI_AO_SetVolume

MI_AO_SetMute

3.9. MI_AUDIO_I2sMode_e¶

Description

Define the working mode of audio I2S TXRX/TX.

Definition

typedef enum

{

    E_MI_AUDIO_I2S_MODE_I2S_MASTER,

    E_MI_AUDIO_I2S_MODE_I2S_SLAVE,

    E_MI_AUDIO_I2S_MODE_TDM_MASTER,

    E_MI_AUDIO_I2S_MODE_TDM_SLAVE,

}MI_AUDIO_I2sMode_e;

Member

Member name	description
E_MI_AUDIO_I2S_MODE_I2S_MASTER	I2S master mode
E_MI_AUDIO_I2S_MODE_I2S_SLAVE	I2S slave mode
E_MI_AUDIO_I2S_MODE_TDM_MASTER	TDM master mode
E_MI_AUDIO_I2S_MODE_TDM_SLAVE	TDM slave mode

Precautions

Determine whether to support the master/slave mode according to different chips.
Related data types and interfaces

MI_AUDIO_I2sConfig_t

3.10. MI_AUDIO_I2sBitWidth_e¶

Description

Define audio I2S TXRX/TX bit width.

Definition

typedef enum

{

    E_MI_AUDIO_BIT_WIDTH_16,

    E_MI_AUDIO_BIT_WIDTH_32,

}MI_AUDIO_I2sBitWidth_e;

Member

Member name description

E_MI_AUDIO_BIT_WIDTH_16 I2S bit width is 16.

E_MI_AUDIO_BIT_WIDTH_32 I2S bit width is 32.
Related data types and interfaces

MI_AUDIO_I2sConfig_t

3.11. MI_AUDIO_I2sFormat_e¶

Description

Define the data transmission format of audio I2S RX/TX.

Definition

typedef enum

{

    E_MI_AUDIO_I2S_FMT_I2S_MSB,

    E_MI_AUDIO_I2S_FMT_LEFT_JUSTIFY_MSB,

}MI_AUDIO_I2sFormat_e;

Member

Member name description

E_MI_AUDIO_I2S_FMT_I2S_MSB I2S standard format; Highest priority

E_MI_AUDIO_I2S_FMT_LEFT_JUSTIFY_MSB I2S left-justified format; Highest priority
Related data types and interfaces

MI_AUDIO_I2sConfig_t

3.12. MI_AUDIO_I2sMclk_e¶

Description

Define the mclk frequency of audio I2S RX/TX.

Definition

typedef enum

{

    E_MI_AUDIO_I2S_MCLK_0,

    E_MI_AUDIO_I2S_MCLK_12_288M,

    E_MI_AUDIO_I2S_MCLK_16_384M,

    E_MI_AUDIO_I2S_MCLK_18_432M,

    E_MI_AUDIO_I2S_MCLK_24_576M,

    E_MI_AUDIO_I2S_MCLK_24M,

    E_MI_AUDIO_I2S_MCLK_48M,

}MI_AUDIO_I2sMclk_e;

Member

Member name	description
E_MI_AUDIO_I2S_MCLK_0	Disable MCLK
E_MI_AUDIO_I2S_MCLK_12_288M	Set MCLK to 12.88M
E_MI_AUDIO_I2S_MCLK_16_384M	Set MCLK to 16.384M
E_MI_AUDIO_I2S_MCLK_18_432M	Set MCLK to 18.432M
E_MI_AUDIO_I2S_MCLK_24_576M	Set MCLK to 24.576M
E_MI_AUDIO_I2S_MCLK_24M	Set MCLK to 24M
E_MI_AUDIO_I2S_MCLK_48M	Set MCLK to 48M

Related data types and interfaces

MI_AUDIO_I2sConfig_t

3.13. MI_AUDIO_I2sConfig_t¶

Description

Define I2S RX/TX config info.

Definition

typedef struct MI_AUDIO_I2sConfig_s

{

    MI_AUDIO_I2sMode_e enMode;

    MI_AUDIO_I2sBitWidth_e enBitWidth;

    MI_AUDIO_I2sFormat_e enFormat;

    MI_AUDIO_SampleRate_e enSampleRate;

    MI_AUDIO_I2sMclk_e enMclk;

    MI_BOOL bSyncClock;

    MI_U32 u32TdmSlots;

} MI_AUDIO_I2sConfig_t;

Member

Member name	description
enMode	I2S working mode
enBitWidth	I2S bit width
enFormat	I2S transmission data format.
enSampleRate	I2S sampling rate
enMclk	I2S mclk frequency
bSyncClock	Whether I2S RX and I2S TX share the clock.
u32TdmSlots	I2S TDM slot number(Only valid in TDM mode)

Related data types and interfaces

MI_AO_SetI2SConfig

MI_AO_GetI2SConfig

3.14. MI_AO_InitParam_t¶

Description

Audio output device initialization parameter.

Definition

typedef struct MI_AO_InitParam_s

{

    MI_AUDIO_DEV AoDevId;

    MI_U8 *u8Data;

} MI_AO_InitParam_t;

Member

Member Name Description

AoDevId AO device number

u8Data Parameter pointer (reserved)
Related data types and interfaces

MI_AO_InitDev

4. ERROR CODE¶

The AO API error codes are shown in the table below:

Error Code	Definition	Description
0xA0052001	MI_AO_ERR_INVALID_DEVID	Invalid audio output device number
0xA0052003	MI_AO_ERR_ILLEGAL_PARAM	Invalid audio output parameter setting
0xA0052006	MI_AO_ERR_NULL_PTR	Input parameter empty indicator error
0xA0052007	MI_AO_ERR_NOT_CONFIG	Audio output device properties are not set
0xA0052008	MI_AO_ERR_NOT_SUPPORT	Operation is not supported
0xA0052009	MI_AO_ERR_NOT_PERM	Operation not allowed
0xA005200C	MI_AO_ERR_NOMEM	Fail to allocate memory
0xA005200D	MI_AO_ERR_NOBUF	Insufficient audio output buffer
0xA005200E	MI_AO_ERR_BUF_EMPTY	Audio output buffer is empty
0xA005200F	MI_AO_ERR_BUF_FULL	Audio output buffer is full
0xA0052010	MI_AO_ERR_SYS_NOTREADY	Audio output system is not initialized
0xA0052012	MI_AO_ERR_BUSY	Audio output system is busy
0xA0052017	MI_AO_ERR_NOT_ENABLED	Audio output device or channel is not enabled
0xA005201D	MI_AO_ERR_NOVASPACE	Audio device mapping buffer failed

5. PROCFS INTRODUCTION¶

5.1. cat¶

Debug info
```
# cat proc/mi_modules/mi_ao/mi_ao0
```
Debug info analysis

Record the current AO usage status and device attributes, and can dynamically obtain information, which is convenient for debugging and testing.

Parameter Description

Parameter		Description
AO Device Attr	DevStatus	AO device status uninit: uninit opened: open sucessfully
	Format	Audio format (Bit width and size end, etc) Currently only support S16_LE (16bit, small end mode)
	SoundMode	Sound mode: mono / stereo
	SampleRate	Sample rate 8k/11.025k/12k/16k/22.05k/24k/32k/44.1k/48k
	PeriodSize	AO starting condition (sample points)
	ChannelMode	AO channel mode Stereo DoubleMono: Currently only support mono output by the left and right channel DoubleLeft: Output two left channels DoubleRight：Output two right channels Exchange: Left and right channel exchange OnlyLeft: Currently only support mono output by the left channel Only Right: Currently only support mono output by the right channel
	MixerSampleRate	Output sample rate after mixing. 8k/16k/32k/48k (Invalid currently)
	DmaBufSize	DMA buffer size
	DmaBusySize	DMA buffer busy size
	DmaFreeSize	DMA buffer free size
	TmpBufSize	Temporal buffer size
	bStart	AO start DMA or not
	bPause	AO pause DMA or not
	FrmCnt	Write data frame count
	DpgaGain	Digital gain: left channel gain, right channel gain
	DpgaMute	DPGA mute: left channel mute, right channel mute
	MI If	MI bind all interface information, that is, all interface information bound to the application layer
	Mhal Left If	MHAL RDMA_L bind all interface information
	Mhal Right If	MHAL RDMA_R bind all interface information
	If Info	Interface volume, mute and other information Volume (left channel gain, right channel gain) Mute (left channel mute, right channel mute)
AO I2S Status	I2sMode	I2S Tx work mode (Only valid when interface is I2S Tx) i2s-master i2s-slave tdm-master tdm-slave
	I2sMclk	I2S Tx Mclk frequency (Only valid when interface is I2S Tx) disable: not use Mclk Other values are the current Mclk frequency
	I2sFmt	I2S Tx data format (Only valid when interface is I2S Tx) I2S-MSB: I2S format LEFT-MSB: I2S left-justified format
	bI2sSync	Whether I2S RX and TX share clock (Only valid when interface is I2S Tx) 1: 4 wire mode，RX and TX share clock 0: 6 wire mode，RX and TX have independent clocks
	TdmSlots	I2S Tx TDM slot number (Tx is TDM mode when interface is I2S)
	I2sBitWidth	I2S TX bit width (Only valid when interface is I2S Tx and the chip supports TDM mode)

5.2. echo¶

Features	Dynamically enable/disable AO device DPGA mute mode
Command	echo set_dpga_mute [LeftMute] [RightMute] [Fading] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[ON/on/1, OFF/off/0] Enable/Disable mute [Fading] Set the fading speed [ID] Device ID
Example	echo set_dpga_mute 1 0 0 > proc/mi_modules/mi_ao/mi_ao[ID]

Features	Dynamically enable/disable AO device interface mute mode
Command	echo set_inf_mute [If] [LeftMute] [RightMute] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[If]Interface to be set [ON/on/1, OFF/off/0] Enable/Disable mute [ID] Device ID
Example	echo set_inf_mute 1 1 0 > proc/mi_modules/mi_ao/mi_ao[ID]
Note	The tiny version does not support this cmd

Features	Dynamically set AO DPGA volume
Command	echo set_dpga_volume [LeftVolume] [RightVolume] [Fading] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[LeftVolume] [RightVolume] Left channel volume, right channel volume [Fading]Set the fading speed of volume
Example	echo set_dpga_volume -10 -10 0 > proc/mi_modules/mi_ao/mi_ao0

Features	Dynamically set AO Interface volume
Command	echo set_inf_volume [If] [LeftVolume] [RightVolume] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[If]Interface to be set [LeftVolume] [RightVolume] Left channel volume, right channel volume
Example	Not support at present

Features	Dynamically enable/disable the dump data function of AO device
Command	echo dump_data [Path] [ON/on/1, OFF/off/0] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[Path] Path to dump data [ON/on/1, OFF/off/0] Enable/Disable the dump data function
Example	echo dump /mnt 1 > proc/mi_modules/mi_ao/mi_ao0

Function	Dynamically enable/disable Singen of AO device
Command	echo singen [SinGen Index] [Enable] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[SinGen Index] Singen ID [Enable] Enable/Disable Singen
Example	echo singen 0 1 > proc/mi_modules/mi_ao/mi_ao0
Note	The tiny version does not support this cmd

Function	Dynamically set channel mode of AO device
Command	echo set_chn_mode [channelMode] > proc/mi_modules/mi_ao/mi_ao[ID]
Parameter Description	[channelMode] channel mode of AO device
Example	echo set_chn_mode 0 > proc/mi_modules/mi_ao/mi_ao0

parameter name	description	Input/Output
enAoIf	AO peripheral	Input
s8LeftVolume	Left channel volume	Input
s8RightVolume	Right channel volume	Input

Parameter Name	Description	Input/Output
enAiI2Sif	Audio I2S TX output peripheral	Input
pstConfig	Audio I2S TX config info	Input

Parameter Name	Description	Input/Output
AoDevId	Audio output device ID	Input
pstAttr	Audio output device attributes	Output

Member name	description
E_MI_AUDIO_FORMAT_INVALID	Invalid data format
E_MI_AUDIO_FORMAT_PCM_S16_LE	PCM Linear 16bit (Little Endian)

Member name	description
E_MI_AUDIO_BIT_WIDTH_16	I2S bit width is 16.
E_MI_AUDIO_BIT_WIDTH_32	I2S bit width is 32.

Member name	description
E_MI_AUDIO_I2S_FMT_I2S_MSB	I2S standard format; Highest priority
E_MI_AUDIO_I2S_FMT_LEFT_JUSTIFY_MSB	I2S left-justified format; Highest priority