[untitled] audio Bluetooth voice chip, wt2605c-32n real-time recording upload technical scheme introduction

be based on WT2605C-32N Introduction to the real-time recording and uploading technology scheme of audio Bluetooth voice chip

         modern society , The development of information technology is particularly rapid , The importance and security of information and data are becoming more and more profound , On some special occasions , Because of the need of work , Or the needs of daily life , It is often necessary to record and retain some important voices . At some point , Recording becomes recording life , An important means of preserving evidence , so , Recording technology is particularly important for our modern life .

         With the development of recording technology , A real-time recording technology is favored by more people , Compared with traditional recording , Real time recording technology breaks through the limitation of equipment , From simple recording equipment to our cloud , Share... Anytime, anywhere , It realizes the interactivity of our recording data , In practical application, it improves the application value of our products , Bring users a more perfect experience .

         Weichuang bosom friend has been committed to becoming a leader in the field of voice Internet of things , Independently developed a real-time recording technology and upload technology , In the recording pen , Recording earphones and other recording equipment are widely used , This real-time recording technology , Small amount of data , Low distortion rate , The noise reduction effect is obvious , Via an external Bluetooth device , Cloud storage can be realized , Cloud instant playback and other functions . More Than This , This recording upload technology is very versatile , It is widely used in all kinds of Bluetooth chips independently developed by Weichuang Zhiyin , Let's briefly introduce one of the schemes ：

WT2605C-32N Introduction to recording upload scheme

1. Program Overview

            Recording upload technology has been used in recording pen in recent years , Recording headphones are widely used , It realizes the interconnection between mobile recording devices and the cloud , Instant play , Instant translation , Simultaneous interpretation has become a highlight of the product , It greatly facilitates our life . To ensure the realization of these functions , It is inseparable from high-quality recording effect , And highly compressed recording data , The recording of this scheme adopts IMA-ADPCM Compression algorithm .IMA-ADPCM (ADPCM Adaptive Differential Pulse Code Modulation), It's about 16bit A lossy compression algorithm for sound waveform data , It takes every pick in the sound stream 16bit The data to  4bit Storage , So the compression ratio is 1:4. And compression / The decompression algorithm is very simple , So it's a low space consumption , A good way to get high quality sound .

2. Schematic diagram

         This scheme adopts WT2605C-32N chip , Can plug in local storage devices , Communicate with Bluetooth transparent chip through serial port , Send the recorded data to the cloud device .

3. Schematic diagram of scheme

4. User agreement

4.1. Protocol command format

         The communication data format is ： Start bit ：1 position ; Data bits ：8 position ; Odd and even bits ： nothing ; Stop bit ：1 position . The instructions sent are in hexadecimal format , The default baud rate is 115200, It can be modified , But not less than 115200 Baud rate . Use the computer serial port debugging assistant , You need to set the parameters of the serial port correctly , The setting is as shown in the figure ：

         Be careful ：“ length ” It means the length + Command code + Parameters + The length of the check sum ,“ Add up and check ” It means the length + Command code + The eighth bit of the cumulative sum of parameters .

4.2. Return code format

         Parameters ：00 ： Indicates successful execution , Start the recording

01 ： Indicates an execution error

02 : Indicates that the file does not exist

4.3. The list of commands

4.3.1. Recording start command (D6)

APP Send this command , Control the recording chip to start recording , At this time, the recording chip will return the success return code of recording , Sending this command during recording returns an error ;

Start recording return code ：

        APP Receive the start recording return code , Then start preparing to process the received recording data , At this time, the chip enters the recording state , Start sending recording data packets at the same time .

         First, the recording chip will send a packet 60 One byte audio packet , The packet data is IMA-ADPCM Audio header of format audio data , Front contains “RIFF” Flag and file size , Note that this time ChunkSize by 0X00000034 Does not contain the length of the current audio packet , Therefore, the header length of the whole audio packet is 0X08+0X34, That is to say 60 The length of bytes . The customer needs to finish recording and receive a complete packet , Rewrite this location .

for example , The audio header ID of the current file is as follows ：

         The next audio header contains Format Chunk Block and Fact Chunk, Customers don't have to care about the actual data .

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The last audio header contains Data Chunk The customer needs to finish recording and receive a complete packet , rewrite DataChunkSize This position

         After sending the audio data , Then an audio packet will be sent , According to the current settings , Every packet C The length is 256 Bytes , Limited to Bluetooth per phone MTU Limit , The amount of data in each packet cannot exceed the default of the mobile phone MTU value , So here according to the minimum MTU value 128 Byte configuration , Put the packet C Two subcontracting A+B Packet sending ,A and B The amount of data per packet is 128 byte , The interval of each packet of data is 10MS about , Every C Packet interval is 60MS about ( According to the recording bit rate , Non modifiable ), Per one C The package data contains the entire nBlockAlign , In the process of sending, even if a packet of data is lost , It will not affect the playback of the whole file .

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         When the customer starts receiving audio packets , Customer APP It is necessary to record the total number of audio packets before the end of recording , such as APP Received... At the end of recording 0X36 Packet audio packet , Then the length of the total audio data is 0X36 * 0X100 = 0X3600;

4.3.2. Recording end command (DA)

        APP Send this command , The recording chip receives the recording end command , Stop sending recording packets , And end the current recording , Return end recording return code ;

End recording return code ：

        APP Receive the end recording return code , Then save the current recording file , And rewrite the data length to the relevant location of the file , As shown in the figure . thus , The recording upload is complete .

5. Program design block diagram

6. Application example

Let's use Weichuang WT-RS2 APP Software for actual testing, recording and uploading function , Start by opening APP, choice MP3 programme ;

         The name of the Bluetooth connection is VT-A782 Bluetooth devices , After successful connection ,APP The interface will print the Bluetooth address of the current Bluetooth device by default MAC Address , Weichuang bosom friend can set different settings for each Bluetooth device MAC Address , Thus forming a separate and unique Bluetooth name , In some applications , Form a unique ID for each product .

         Click on APP Interface start recording flag , here APP Create a recording file by time , At this point, the recording data is received , Every A and B Packet interval 10MS, Every C Packet interval 60MS, Until you click APP End recording button , here APP Show end of recording . At this point, the recording file has been created , Customers can go through APP The interface sends the recorded files to the computer or other players for playback by sharing ！

About us

         As a high-tech enterprise focusing on voice technology research , Always adhere to “ Good service engineers ” Target , Take the standardization of voice interaction devices in the industry as the direction , Committed to making complexity simple , Provide fast voice 、 Intelligent Internet of things application solutions .

        WT588F02B、WT2003H Application design scheme of series voice chip , On the smart alarm clock 、 Smart water cup 、 There are mature application cases in the field of consumer electronics such as atomizer . The application of consumer electronic products is an important development field of the company , future , Weichuang Zhiyin will launch standardized voice chips in more industries , Further enhance the design experience of Engineers , Enabling standardization in the consumer electronics industry .