Design plan for realizing MP3 player function based on ARM

Abstract: In order to overcome the shortcomings of MP3 currently on the market such as small storage capacity, high price, complex operation, and single song playback, an MP3 player based on ARMLPC2131 was designed. The player is mainly composed of audio decoding module and music file access module. The experimental results show that this design realizes the automatic playback of songs stored in a USB flash drive in the order set by oneself, and has the characteristics of large storage capacity, low price, simple operation, and many types of playback, and has certain practical and promotion value. .

0 Preface

MPEG (Moving Picture Experts Group) is the abbreviation of Moving Picture Experts Group. MP3 is the abbreviation of MPEG Audio Layer 3, which is the MPEG layer 3 audio coding standard. Using the MP3 standard to encode audio data can not only achieve a larger music data compression ratio, but also obtain better music playback quality. There are two existing MP3 decoding solutions at home and abroad: hardware and software decoding. Hardware decoding using a dedicated decoding chip has poor flexibility, and the hardware decoding chip is expensive. Software decoding based on processor development platforms such as DSP or ARM has good expansion capabilities and high cost performance.

ARM (Advanced RISC Machines) can be considered as the name of a company, as a general name for a type of microprocessor, and as a technology. At present, microprocessors using ARM technology intellectual property (IP) cores, commonly known as ARM microprocessors, have spread across various product markets such as industrial control, consumer electronics, communication systems, network systems, and wireless systems. The microprocessor application of ARM technology accounts for more than 75% of the market share of 32-bit RISC microprocessors. ARM technology is gradually penetrating into all aspects of our lives.

This article uses an ARM microprocessor as the control and management unit of the entire audio playback system. The starting point is to study the application of digital audio technology in ARM embedded systems, and design a digital audio playback system based on ARM embedded systems by combining the two cutting-edge technologies of digital audio and ARM embedded systems.

1 Overall plan of the system

This article introduces a new MP3 player design based on ARM LPC2131. This design idea uses the LPC2131 controller as the core to cooperate with the audio decoding module and music file access module. This can overcome the contradiction between the high price and sound quality of MP3 in the market today, and has the advantage of massive storage. The overall design scheme is shown in Figure 1, which uses ARM LPC2131 as the controller to control the audio decoding module and music file access module.

Figure 1 System overall diagram

2 Hardware design

2. 1 Audio decoding module design

The audio decoding module contains a high-performance, low-power DSP processor core VS_DSP4 with independent property rights, working data memory, providing 5 KB instruction RAM and 0. 5 KB data RAM for user applications. Serial control and data interface, 4 general-purpose I/O ports, 1 UART, 1 high-quality variable sampling rate ADC and stereo DAC, 1 headphone amplifier and ground buffer.

2. 2 Music file access module design

The USB host mode of CH375 supports parallel interface and serial interface. In USB host mode, CH375 supports various commonly used USB full-speed devices. The external ARM needs to write firmware programs to communicate with USB devices according to the corresponding USB protocol. But for USB storage devices, CH375 has built-in relevant protocols. Normally, the external ARM can communicate directly without writing firmware programs. The schematic design diagram is shown in Figure 2.

Figure 2 Music file access module