#audiochip

I. Application Background

With the development of urban intelligent transportation, accessibility facilities are receiving increasing attention. For visually impaired individuals, relying solely on visual traffic signals is insufficient for safe street crossing. To address this, we have developed acrosswalk auditory guidance system for traffic light intersectionsbased on theKT142C voice chip, which uses audible cues to guide visually impaired pedestrians safely across streets.

II. Solution Overview

The system is installed on traffic light poles and operates in sync with pedestrian signals:

During green light: Plays rhythmic prompts to guide crossing.

During red light: Plays a different rhythmic pattern to indicate waiting.

Light-sensitive smart adjustment: Automatically switches between "daytime" and "nighttime" modes based on ambient brightness to avoid noise disturbance at night.

Volume and modes can be flexibly configured via serial commands or configuration files to adapt to different intersection requirements.

III. Advantages of KT142C in This Solution

1.Built-in storage, no external Flash required

The chip features320KB of built-in storage, capable of storing multiple audio prompts directly without requiring external SPI Flash, resulting in simpler hardware design.

2.Supports direct audio updates via USB

When connected to a PC via USB, the chip appears as a virtual USB drive, allowing prompt audio updates at any time without dedicated programming tools, making maintenance convenient.

3.Flexible playback control

Supports serial command control (e.g., playing specific audio, adjusting volume, looping playback).

Supports IO trigger playback, enabling direct interfacing with traffic light control boards.

Supports combined playback for seamless transitions between multiple audio segments.

4.Low-power design

The chip supports low-power mode (as low as 2µA), suitable for intersection devices operating continuously year-round. It can also be controlled via light sensors for on/off management.

5.Selectable audio output modes

PWM direct drive for speakers (0.5W/8Ω).

DAC output for external amplifiers (e.g., HAA2018), suitable for higher-power scenarios.

IV. Technical Implementation Details

✅ Audio File Planning

001.mp3 : Green light prompt tone (frequency 300–500Hz, 160ms on, 500ms off).

002.mp3 : Red light prompt tone (frequency 300–500Hz, 200ms on, 300ms off).

003.mp3 : Green light final 3-second prompt tone (accelerated rhythm).

Configuration file  config.txt  sets trigger modes, volume, output mode, etc.

✅ Brightness Sensing Control

An external light sensor detects ambient brightness, processed by an MCU:

Brightness > 200 LUX for 60 seconds → Daytime mode (volume ≤ 65 dB).

Brightness < 200 LUX for 60 seconds → Nighttime mode (volume ≤ 45 dB).

Nighttime mode persists for 180 minutes → Mute mode activated.

✅ Integration with Traffic Light Control System

IO level triggers playback of corresponding prompt tones.

Serial commands can also receive traffic light status instructions for more complex auditory guidance logic.

V. Measured Parameter Table

VI. Testing and Validation

We used:

Digital oscilloscope → to detect output waveform and frequency.

Spectrum analyzer → to analyze audio frequency range.

Sound level meter → to measure actual sound pressure levels.

Serial debug assistant → to verify command responses.

Test results show that the KT142C performs stably under continuous operation, temperature variations, and voltage fluctuations, meeting the long-term operational requirements of crosswalk guidance devices.

VII. Customer Benefits

Easy Integration: Simple peripheral circuitry—only two capacitors required for operation.

Convenient Maintenance: USB-based audio updates, no device disassembly needed.

Smart Control: Supports light-sensing and timing control for balanced guidance and environmental protection.

High Reliability: Industrial temperature range suitable for harsh outdoor environments.

VIII. Technical Support and Resources

For more detailed design materials, schematics, configuration file examples, and other resources related to the KT142C in this application, visit our official resource repository.

Introduction: Protecting Health Starts with Audible Air Safety

"Clothing, food, shelter, and transportation" - the safety of our living environment is paramount. In modern life, with new home renovations and new furniture, formaldehyde and other harmful gases become hidden health threats. National standards stipulate that indoor formaldehyde concentrations exceeding 0.08mg/m³ are considered excessive, and long-term exposure to excessive environments can severely impact the respiratory system and even cause serious diseases.

Traditional detectors often rely solely on beeping sounds or screen readings, with information transmission not being intuitive enough, especially with limited effectiveness during emergencies. How can we make air detection more humane, more audible, and easier to understand? The KT148A voice chip, with its high sound quality, strong drive capability, low power consumption, and flexible control, provides a complete voice prompt and interaction solution for smart formaldehyde/PM2.5 detectors.

1. Application Value of KT148A Voice Chip in Formaldehyde Detectors

1. Real Voice Broadcast for More Intuitive Information Transmission

Directly broadcasts formaldehyde concentration, PM2.5 values, temperature and humidity data, avoiding user misinterpretation of screen information.

Supports bilingual prompts in Chinese and English, adapting to different user groups.

2. Multi-Level Voice Warnings for Clearer Risk Alerts

Plays different prompts based on concentration thresholds: "Within normal range," "Slightly exceeding limits," "Severe pollution, please address immediately."

Supports combined playback, such as "Formaldehyde concentration: 0.15mg/m³, exceeding limits, recommend ventilation."

3. Operation Guidance and Status Feedback

Power-on welcome messages, voice-guided usage instructions.

Sensor calibration prompts, low battery reminders, voice explanations for error states.

4. Enhancing Product Competitiveness and User Experience

Voice interaction elevates product technological sophistication and human-centric design.

Suitable for detection devices in various scenarios including homes, vehicles, and offices.

2. Core Advantages of KT148A Voice Chip

The KT148A is a high-performance 32-bit DSP voice chip in SOP8 package with 420KB built-in storage, supporting up to 420 seconds of audio content, featuring the following outstanding characteristics:

✅ High-Fidelity Sound Quality, Clear and Natural Voice

Supports 16KHz sampling rate for high clarity voice prompts without noise.

Built-in audio decoding hardware ensures stable, non-stuttering sound.

✅ Direct Speaker Drive with Simple Circuitry

Can directly drive 8Ω/0.5W speakers without external amplifiers, reducing BOM costs.

Supports PWM output for excellent sound quality, suitable for alarm-type prompts.

✅ Ultra-Low Power Consumption for Extended Battery Life

Standby current only 25μA, ultra-low power mode can drop to 1.7μA, ideal for battery-powered devices.

Supports wake-up mechanism, operating only during playback, greatly extending usage time.

✅ Flexible Control and Voice Management

Supports one-wire serial control, requiring only one IO to trigger multiple voice segments.

Voice content can be independently updated via USB-to-TTL tools, no factory return needed.

Supports 16-level volume adjustment to adapt to different environmental volume needs.

✅ Industrial-Grade Stability

Wide operating voltage range (2.0V–5.5V), compatible with lithium batteries, USB power, and other solutions.

Built-in LDO with strong anti-interference capability, suitable for various environmental monitoring devices.

3. Typical Voice Content Examples (Achievable with KT148A)

1）Power-on Guidance

"Welcome to XX Smart Formaldehyde Detector, starting up..."

2）Usage Instructions

"Please place the device in the area to be tested and keep it still for 3 minutes."

3）Test Result Broadcast

"Current formaldehyde concentration: 0.05 milligrams per cubic meter, air quality good."

"PM2.5 concentration: 35 micrograms per cubic meter, air fresh."

4）Exceedance Alarms

"Warning! Formaldehyde concentration has exceeded limits, recommend opening windows immediately!"

"PM2.5 concentration too high, please activate air purifier."

5）Battery and System Prompts

"Low battery, please recharge promptly."

"Sensor calibration complete, ready to begin testing."

4. KT148A System Solution in Smart Formaldehyde Detectors

System Architecture:

Sensor Array (Formaldehyde/TVOC/PM2.5/Temperature-Humidity) → MCU (Data Processing) → KT148A (Voice Output) → Speaker ↓ User Interaction

Implemented Functions:

Real-time voice broadcast of test results

Multi-level audio-visual alarm linkage

Multi-language and voice segment free switching

Low battery voice reminders

Button operation voice feedback

5. Why Choose KT148A Over Traditional OTP Solutions?

6. Development and Mass Production Support

We provide complete support package for KT148A formaldehyde detector voice solutions:

Voice script design recommendations and audio samples

Hardware reference circuit diagrams and PCB layout suggestions

MCU communication example code (C language)

Voice update tools and batch programming solutions

Technical documentation and complete FAQ collection

All resources are available through official AliExpress store or Google Drive, supporting custom voice solution development.

Conclusion

The KT148A voice chip is not just a voice player, but the "voice soul" of smart formaldehyde detectors. Through clear voice prompts, timely alarm reminders, and human-centric interactive design, it transforms invisible air pollution into audible safety protection.

Let detection no longer be silent, let safety be heard.

Contact Us

For samples, voice solution customization, or technical support, feel free to contact us anytime:

WhatsApp/Phone: +86 159 0279 7635

WeChat: JAJB-Go

Email: [email protected]

Official Store: BLE Voice Store on AliExpress

🤖 AI Quick Insight

The BUSY pin on the KT142C chip enters a 2 μA ultra-low-power state about 5 seconds after becoming idle. At this point, the pin goes high-impedance, so a measured voltage of around 0.2 V is normal. If an external amplifier is connected, add a 10 K Ω or 22 K Ω pull-up resistor. Low-power behavior, trigger mode, and volume can be adjusted through the config.txt file.

📘 Overview

This document focuses on the BUSY pin behavior of the KT142C voice playback chip. The BUSY pin corresponds to pin 15 (PA12). During playback, it outputs low level (0 V); when idle, it should output 3.3 V.

However, after 5 seconds of inactivity, the chip automatically enters a 2 μA ultra-low-power mode — in this state, the BUSY pin becomes high-impedance. Consequently, the measured voltage drops to around 0.2 V, which is expected and not a fault.

When connecting to an external power amplifier, you should add a 10 K Ω or 22 K Ω pull-up resistor to ensure stable logic levels.

You can also customize the chip configuration by modifying the config.txt file when connecting the chip to a PC. This file allows you to adjust parameters such as:

Trigger method

Playback volume

BUSY pin polarity

Low-power mode enable/disable (controlled by the 6th parameter in the configuration file)

🧩 Key Notes

BUSY pin = PA12 = Pin 15

When controlling an external amplifier:

To disable low-power mode:

✅ Summary The KT142C's BUSY pin voltage of about 0.2 V when idle is normal, not a malfunction. This behavior results from the chip entering 2 μA ultra-low-power mode after 5 seconds of inactivity, during which the BUSY pin is high-impedance. To ensure compatibility with external circuits, add a pull-up resistor, or disable low-power mode through configuration.

In the field of smart home, there has always been room for improvement in the sound experience of doorbells and home appliances. The monotonous "ding - dong" sound when the courier rings the doorbell and the uniform prompt sound when family members touch the porch button reflect this "sound shortcoming". However, the KT148A voice chip from Shenzhen Qingyue Electronics, in the SOP8 package form, has successfully broken this dilemma, bringing a qualitative improvement to the sound of doorbells and home appliances.

The Musical Magic Inside the 8 - pin Chip

Despite its small size, the KT148A has professional - level audio capabilities:

Volume Adjustment: It supports 15 - level volume adjustment, enabling seamless switching from a gentle morning reminder to a clear alert in a noisy environment.

Voice Storage and Customization: With up to 224 voice addresses built - in, it allows for custom voice content. It can play classic music clips or record a child's laughter as a unique prompt.

Voltage Adaptability and Low Power Consumption: Its 2.0V - 5.5V wide - voltage design perfectly adapts to the low - voltage power supply system of smart homes. The static current is only 25uA, and it supports an ultra - low - power mode down to 1.7uA, showing excellent battery life performance.

Anti - interference Ability: Through hardware decoding and built - in DSP processing, it can effectively resist electromagnetic interference from home appliances, ensuring clear and stable ringtones in complex electrical environments. Moreover, the SOP8 package takes up very little space, facilitating the design of ultra - thin smart doorbells and embedded home appliance panels.

Reshaping the "Sound DNA" of Smart Homes

Stunning Performance in the Smart Doorbell Field

In the field of smart doorbells, the KT148A performs outstandingly. Users can select a variety of preset ringtones through one - wire serial port control and also customize the playback of combined voices, greatly improving the satisfaction of visitors' experience.

Application in Smart Home Appliances

Regarding smart home appliances, the prompt sounds driven by this chip can distinguish different states through melody differences, replacing the monotonous beeping.

Innovation in Smart Home Linkage Scenarios

In smart home linkage scenarios, the KT148A brings more creative applications. For example, when the fingerprint lock is verified, a short welcome melody is played simultaneously; when the device completes an operation, a brisk prompt sound automatically rings. This "scenario - based sound effect" gives warmth to cold appliances and significantly improves the user experience.

Reasons Why Smart Home Manufacturers are Rushing to Order

Convenient Voice Replacement: The KT148A supports users to change voice content by themselves. It can be burned through a serial port tool without the need for an additional programmer, greatly reducing the mass - production threshold and production costs.

Easy Development and Integration: The one - wire serial port control method enables engineers to integrate it easily, significantly shortening the development cycle.

Strong Environmental Adaptability: This chip supports an industrial - grade temperature range (-40℃ to +85℃), adapting to various environments. It has been widely used in smart doorbells, smart home appliances, security alarms, and other products.

Make Your Product "Sound" Appeal to the Heart

Sound has become a differentiating competitive advantage for smart homes. Choosing the KT148A chip can seize the market opportunity. Contact Qingyue Electronics to obtain complete development materials and technical support, including user manuals, reference designs, and debugging guides. As a well - known domestic voice chip solution provider, Qingyue Electronics is based on chip design and audio codec algorithms, and is constantly innovating in the fields of audio playback, 2.4G wireless audio, Bluetooth BLE artificial intelligence, and integrated circuit electronic product applications.

The KT148A chip supports programming on user - owned boards, which is highly suitable for simple sample - sending scenarios. When performing the programming operation, a 6 - pin "DOWN - PIN" interface socket needs to be reserved. The download function is achieved through the UART serial port, and this download method is common to both the one - wire serial port version and the button version. Moreover, the programming depends on the PC - side host - computer software.

Hardware Reference Circuit and External Interface

The hardware reference circuit is centered around the 6 - pin "DOWN - PIN" interface socket.

Regarding the specific connection method of this 6 - pin socket, users can build additional circuits according to relevant definitions.

Programming Methods and Conditions

1.Download Method: Both the one - wire serial port version and the button version use the method of passing through the serial port UART and opening the PC - side host - computer software for downloading.

2.Conditions Required to Enter Downloading:

Condition 1: Pin 5 of the chip needs to be grounded for power - on. Only in this way can the chip smoothly enter the downloading state.

Condition 2: The chip needs to be powered, and a power supply voltage of around 3.3V - 5V is feasible.

Condition 3: Connect a USB - to - TTL chip similar to CH340G, and at the same time, open the PC - side host - computer software. At this point, the downloading operation can be carried out.

3.Minimum Peripheral System Circuit: The minimum peripheral system circuit of the KT148A does not require isolation treatment, and it will not affect the downloading process. For example, R1 and the indicator light can be retained normally.

4.Core Programming Logic: The core logic of the entire programming process is to first short - circuit pin 5 of the chip to the ground, and then perform the power - on operation. When connecting the UART port, special attention should be paid to the cross - connection. After completing these steps, you can click the PC - side software for downloading, thus achieving the programming of KT148A one by one on the board.

Other Programming Methods

In addition to the above - mentioned programming method on user - owned boards, we also provide a download board for programming. With this download board, the downloading operation can be completed first, and then the chip can be surface - mounted. The introduction document of the download board is as follows：

Finally, summarize the entire document using AI:

The voice - enabled electronic sphygmomanometer, with its voice - prompt function, offers voice announcements throughout the entire process from pre - measurement to the presentation of measurement results. This provides great convenience for the elderly and those with poor eyesight. The voice chips and Bluetooth chips of Qingyue Electronics are widely used in fields such as electronic medical devices, medical auxiliary equipment, physical health index monitoring, and various measuring instruments. They provide professional voice chip and Bluetooth technology development services to manufacturers of equipment such as electronic sphygmomanometers, blood glucose meters, and body fat scales.

Design Principle of the Voice Chip Solution for electronic Sphygmomanometers

Circuit Connection and Signal Flow

The electronic sphygmomanometer circuit is connected to the voice circuit, and the voice circuit is connected to the speaker. The data signal generated by the electronic sphygmomanometer circuit is transmitted to the voice circuit. This signal not only serves as an input but also controls the voice circuit to generate an audio signal, which is finally output as sound by the speaker.

The Coordination Mechanism of Voice and Address Code

Different voices are set within the voice circuit, each corresponding to a specific address code. The electronic sphygmomanometer circuit has an in - built address - code data generation circuit and a comparison circuit. The voice circuit is connected to the electronic sphygmomanometer through serial data lines, data feedback lines, and data confirmation lines. Through this connection, the voice - enabled electronic sphygmomanometer can report the real - time measured blood pressure value in a voice - based manner.

Application Practice of KT148A Voice Chip in electronic Sphygmomanometers

The Implementation Architecture of Voice Function

The KT148A voice chip is selected to achieve the voice - playing function of the electronic sphygmomanometer. This chip pre - records human - friendly voices, is responsible for storing and outputting voice information, while the speaker is tasked with outputting audio voices.

The Process of Data Processing and Voice Output

The single - chip microcomputer obtains digital blood - pressure data from the electronic sphygmomanometer according to the control information. After data processing, it controls the voice chip to output the corresponding human - friendly voices to the speaker.

Product Features of KT148A Voice Chip

The KT148A voice chip adopts the SOP8 surface - mount package form. It has the capabilities of anti - interference and shock - resistance. With superior performance, high reliability, beautiful sound quality, and good stability, it has been widely used in the market, enabling users to select according to product requirements.

Voice Content of KT148A Voice Chip in electronic Sphygmomanometers

Welcome to use the intelligent electronic sphygmomanometer. Please keep quiet.

Measurement error. Please measure again.

Systolic pressure.

Diastolic pressure.

Pulse.

Kilopascal.

Battery power is low.

Mean arterial pressure.

The scheduled time has arrived. Please measure.

Measuring. Please do not move your arm.

Please do not press your arm under the lower side of the cuff.

Your blood pressure is on the high side. ......

Pinout diagram and corresponding table for the KT148A voice chip:

Introduction: The KT142A is a robust voice chip that seamlessly integrates MP3 hardware decoding capabilities. It supports multiple storage media and offers flexible playback control mechanisms. This article will meticulously detail the process of applying the KT142A chip in practical projects, spanning from audio file handling to final debugging.

I. Audio File Preparation and Processing

1.1 Supported Audio Formats

MP3 Format: It provides full - bit - rate support for 11172 - 3 & ISO13813 - 3 Layer3 audio decoding.

Sampling Rate Support: Accommodates sampling rates of 8/11.025/12/16/22.05/24/32kHz.

Sound Effect Modes: Features sound effect modes including Normal, Jazz, Classical, Pop, and Rock.

1.2 Audio File Optimization Recommendations

Professional Audio Editing Tools: We recommend using Adobe Audition CS5.5 or GoldWave.exe for audio editing. These tools offer advanced features for enhancing audio quality.

Silent Segment Removal: Especially in applications involving combined audio playback, it is crucial to remove the silent parts at the start and end of the audio files. This ensures smooth and continuous playback.

File Naming Standardization: Adopt the "001xxx.mp3" naming format. This standardization simplifies file management and playback control, making it easier to organize and access audio files in your project.

II. Hardware Connection and Configuration

2.1 Reference Circuit Design

Power Input: The power input range is 2.6V - 5.2V. For optimal performance, 4.6V is recommended, which can be achieved by connecting diodes in series.

Audio Output: The chip supports DAC output via Pin 9 and PWM direct drive through Pins 13/14. This flexibility allows for seamless integration with various audio output devices.

Serial Communication: The default baud rate for serial communication is 115200, but it can be configured according to project requirements.

2.2 Key Pin Descriptions

III. Software Development and Debugging

3.1 Serial Communication Protocol

The KT142A adheres to a standard serial communication protocol. The data packet format is as follows:$S | VER Len | CMD Feedback | para1 para2 checksum | $0

This format ensures reliable and efficient communication between the chip and other components in the system.

3.2 Essential Development Steps

Initialization Phase: After power - on, allow 1 - 1.5 seconds for the chip to complete its initialization process. This ensures that all internal components are properly configured and ready for operation.

Device Detection: Send the command 7E 3F 00 02 00 00 EF to check if the device is online. This step is crucial for establishing communication with the chip.

Playback Control: Based on project requirements, send commands for functions such as play, pause, and stop. These commands enable precise control over the audio playback.

Status Monitoring: You can obtain the playback status either through the BUSY pin or by sending specific query commands. This real - time status information helps in debugging and ensuring smooth operation.

IV. Practical Application Cases

4.1 Bus Arrival Voice Announcement System

Implementation Strategy:

Audio File Preparation: Record announcements like "Bus No. XX is approaching" and "XX Station has arrived". Name these files in the format "001ApproachingPrompt.mp3", "002ArrivalPrompt.mp3", etc. This naming convention simplifies file management and retrieval.

Hardware Connection: Connect the KT142A to the in - vehicle MCU via a serial port. Use PWM to directly drive the in - vehicle speaker, which has an impedance of 8 ohms and a power rating of 5W. This setup ensures high - quality audio output.

Control Logic:

// Function to play combined voice when the bus arrives void play_bus_arrival(int bus_number, int station_number) { uint8_t cmd[] = {0x7E, 0x21, 0x00, 0x06, (bus_number/10), (bus_number%10), (station_number/10), (station_number%10), 0xEF}; send_serial_command(cmd, sizeof(cmd)); }

Optimization Tips: Utilize the built - in storage space to store frequently used prompts. Use a TF card to store voice content that may change occasionally. To enhance user experience, set the volume memory function by sending the command 7E 06 00 02 01 1E EF.

4.2 Community Access Control Voice Prompt System

Implementation Strategy:

Audio File Organization: Categorize audio files into folders. For example, use "01" for welcome messages, "02" for warning messages, and "03" for operation prompts. Name files like "01/001WelcomeHome.mp3", "02/001IllegalEntry.mp3". This hierarchical organization simplifies file management.

Hardware Design: Connect the access control controller to the KT142A. Use the DAC output to connect to a 3W external amplifier. Configure Pin1 to be grounded through a 1K resistor to select the DAC mode. This setup optimizes audio output quality.

Function Realization:

// Function to play different voices based on access control status void play_door_message(int status) { switch(status) { case 1: // Normal door opening send_command(0x0F, 1, 1); // Play the 001 file in folder 01 break; case 2: // Illegal entry send_command(0x0F, 2, 1); // Play the 001 file in folder 02 break; case 3: // Door not closed properly send_command(0x28, 3, 0); // Loop - play a random file in folder 03 break; } }

Power - saving Design: When no one is in the vicinity, send the command 7E 0A 00 02 00 01 EF to put the chip into low - power mode. When a human - body sensor is triggered, send any command to wake up the chip. This design helps conserve power and extend the device's operating time.

V. Solutions to Common Problems (from the User Manual FAQ)

5.1 No Response After Chip Soldering

Problem Scenario: After soldering the KT142A to the PCB, there is no virtual drive display when connecting to USB.

Solutions:

Power Voltage Check: Verify that the voltage at Pin11 is within the range of 3.3V - 5.2V. Incorrect voltage can lead to improper operation.

Pin10 Voltage Confirmation: Ensure that the output voltage of Pin10 is 3.3V. An abnormal voltage may indicate chip damage.

BUSY Pin Status Inspection: When connected to USB, the BUSY pin (Pin15) should flash rapidly. If not, it may signal a connection or chip functionality issue.

USB Cable Verification: Avoid using a charging - only USB cable. Ensure the use of a standard 4 - wire data cable for proper communication.

5.2 Incomplete Audio Playback

Problem Scenario: When using the DAC output to connect to an amplifier, the beginning part of the audio is cut off.

Solutions:

Hardware Adjustments: Reduce the amplifier enable capacitor from 1μF to 10nF or 100nF. Also, synchronize the amplifier enable signal with the BUSY pin of the KT142A. These adjustments help ensure proper amplifier operation.

Software Modifications:

// Function to add a delay before playing audio void play_with_delay(uint8_t folder, uint8_t file) { set_amplifier_enable(1); // Enable the amplifier delay_ms(150); // Wait for the amplifier to stabilize send_command(0x0F, folder, file); // Send the play command }

Audio Editing: Use Adobe Audition to add a 200 - ms silent part at the start of the audio file. Save it as an MP3 file with a sampling rate of 16kHz. This modification helps avoid audio truncation.

5.3 Audio Download Problem in Mass Production

Problem Scenario: While the sample test is successful, efficient audio file downloading in mass production becomes a challenge.

Solutions:

Built - in Storage Approach: Use the PC tool provided by the manufacturer to perform batch downloads via the serial port. The total file size should not exceed 332KB, which can store approximately 160 seconds of high - quality audio.

External SPIFLASH Approach:

# Python script for automated audio file flashing import os import serial def flash_audio_files(port, folder_path): ser = serial.Serial(port, 115200, timeout = 1) for file in os.listdir(folder_path): if file.endswith('.mp3'): with open(os.path.join(folder_path, file), 'rb') as f: data = f.read() ser.write(b'\x7E\x03\x00') # Start transmission command ser.write(len(data).to_bytes(2, 'big')) ser.write(data) ser.write(b'\xEF') # End flag ser.close()

Production Testing: After downloading each chip, send the command 7E 46 00 02 00 00 EF to query the firmware version. Randomly sample and test the playback function by sending 7E 03 00 02 00 01 EF to play the first voice segment. This helps ensure the quality of mass - produced chips.

5.4 Low - Voltage Application Problem

Problem Scenario: When powered by two dry batteries (3V), the sound output is low, and the chip may reset.

Solutions:

Hardware Enhancements: Short - circuit Pin10 and Pin11 of the chip. Add a capacitor of ≥22μF (226) to Pin11 to stabilize the power supply. Thicken the power - supply trace to reduce line impedance. These hardware modifications improve power stability.

Software Settings:

// Initialization settings during power - on void init_chip() { send_command(0x1A, 0, 1); // Select PWM direct - drive mode for higher efficiency send_command(0x06, 1, 20); // Set the volume to 20 with memory function send_command(0x0B, 0, 3); // Set the baud rate to 9600 for better stability at low voltage }

Audio Optimization: Use audio files with an 8kHz sampling rate. Increase the volume of the audio source file through software, but be cautious to avoid clipping. This optimization improves audio quality at low voltage.

Conclusion: The KT142A voice chip, with its user - friendly interface, powerful functionality, and versatile application methods, is an excellent choice for a wide range of voice - prompt projects. By following the methods and solutions presented in this article, developers can effectively address typical problems encountered in practical projects and achieve rapid system integration.

Technical Support and Sample Purchase:

WhatsApp: +86 159 0279 7635

Official Store: BLE Voice Store

Complete Technical Documentation: Refer to the Google Drive link in the user manual.