Project Description

Wuhan Xinyuan Semiconductor CW32 series MCU is used as the main control of a compact MP3. It adopts CW32L series low-power chips.

If you like my project, please like and collect, thank you! More high-quality works will be launched in the next issue.

Bilibili UP Main: Mr. Lei talks about electronics, and the QQ Q&A group 458720579.

Open-source protocol

GPL3.0

Project-related features

1.Lithium battery power supply, TYPE-C interface charging, power display;

2.Power consumption management;

3.3.5mm audio output interface, no external speaker mode can be designed;

4.Screen display: lyrics name, lyrics, battery level, etc.; The brightness and time of screen use can be set for power consumption management;

5.SD card insertion, and support reading song information;

Project properties

This project is the first public and is my original project. The project has not won an award in another competition.

Project progress

May 20 began to draw schematics.

May 23 draw PCB.

May 27, the welding was completed, and the adjustment procedure began.

June 15,The first edition was completed.

June 28th,The second edition began.

July 12th,It was all completed.

Design Principles

Design the framework

The above picture shows the main system framework of the entire MP3, which first provides 4.2V voltage from the battery to the power management, and then converts the power management into 3.3V and 1.8V voltages to the whole system.

The main controller extracts the information from the memory card into binary input and puts it into the audio decoder chip (VS1053B), and displays the information on the OLED display at the same time. With independent buttons, you can control information such as playback and pause.

Design difficulties

Low power consumption (solution: the power supply uses the industry's leading charge pump step-down chip, and the chip adopts the CW32L series low-power main controller)

1. Master control

The main control adopts CW32L031C8U6, ARM® Cortex-M0®+ 32-bit low-power microcontroller 64K byte FLASH, 8K byte RAM, up to 48MHz main frequency, supports up to 39 I/O interfaces, completely surpasses STM32, and has a wide range of applications in aerospace and national defense and military.

It is cost-effective, and you can apply for a development board for free. 2021 is the 20th anniversary of the establishment of CW, and it is also a year for Xinyuan Semiconductor to accelerate its high-quality development, and it is also a year for a major turning point in the dual-core strategy of transforming listed companies from agency distribution to chip design and agent distribution. In the future, the company will continue to move forward steadily.

In the field of chip research and development, we will be specialized and stronger, and actively respond to and implement the country's great strategy of domestic substitution in the chip industry.

CW32 Eco Community:

WeChat public account search: "CW32 Ecological Community"--> click to follow, you can apply for free development board and chip, friends, give full play to your creativity and imagination, work together, and boost the development and development of CW32!!

2. Audio decoding chip

VS1053B is a high-performance audio codec module, supporting: MP3/WMA/OGG/WAV/FLAC/MIDI/AAC and other audio formats decoding, and support: OGG/WAV audio format recording, support high and low pitch adjustment and EarSpeaker spatial effect settings, very powerful.

It includes a high-performance, patented, low-power DSP processor core VS_DSP4, working data memory, 16 KiB of instruction RAM and more than 0.5 KiB of data RAM for user applications to run with any hardened decoder, serial control and input data interfaces, and up to eight available general-purpose I/O pins.

3. Independent buttons

The individual buttons use light touch buttons as well as paddle buttons, which are ergonomic and very comfortable to press.

4. Power management

The power management adopts the battery charging chip TP4054, which is a complete monolithic lithium-ion battery constant current/constant voltage linear power management chip. Its thin size and small outer packaging make it easy to use. What's more, the TP4054 is specifically designed to work with USB power delivery specifications. Thanks to the internal MOSFET structure, it is not required for the application.
External resistors and blocking diodes. During high-energy operation and high peripheral temperatures, thermal feedback can control the charging current to reduce chip temperature.

The power chip uses TX4310B is a low-noise, constant-frequency (1.2MHz) switched-capacitor voltage doubler.
TX4310B produces a stable output voltage from a 1.8V to 5V input. The low number of external components (one fast capacitor and two small bypass capacitors at VDD and VOUT) makes the chip ideal for small, battery-powered applications.
The charge pump architecture maintains a constant switching frequency for no-load regulated output and reduced output and input ripple.

5.OLED display

OELD uses 0.96-inch blue 128x64 pixel resolution monochrome 30PIN, and the main control chip is SSD1315.

6. External interface circuit

The external circuit has a TF card slot, a download interface and a 3.5mm audio interface, here we note that the TF card uses SPI communication, and uses a 10K resistor to pull up to ensure the stability of communication.

Software Description

The program is more complex, using a state machine and file system, adding the screen off to enter the low-power mode, thanks to the excellent low-power performance of our CW32L031 series, you can play music continuously for 12 hours,

We need to place the font file in the SD card, download it in the attachment of my project, and write it to the SD card through the card reader to work, otherwise it will prompt when it is opened.

Physical display

Design considerations

We have to be extra careful when installing the enclosure, violent installation may break the dial button!

I put the music playing at the same time as the attachment, so you can download it by yourself.

Other

Bilibili video link: https://www.bilibili.com/video/BV1yV4y1q7zU/