Audio player design example

Document created by Fernanda Servin Employee on Apr 12, 2016Last modified by Fernanda Servin Employee on Apr 13, 2016
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The Audio Player Design Example, based on an NXP LPC2138 ARM7-based microcontroller, delivers high-quality, uncompressed, 16-bit digital audio playback. This design allows engineers to add MP3 music or sound effects to a variety of consumer applications at a very low cost. Entertaining sounds could be added to children's items or music clips could be easily added to products targeted at teens. There is no limit to the number of existing applications that could be enhanced by inexpensively adding high-quality sound or music.

Block Diagram



  • Audio Player



Below are recommended microcontrollers for use in implementing this design to a system.

Comparison Table


ProductPinsOn-Chip FlashOn-Chip RAMComments
LPC213864512KB32KBBase microcontroller used in the design example.
LPC213664256KB32KBA lower-cost microcontroller with the same amount of on-chip RAM but with only half the on-chip flash memory.
+ 8KB
An upgraded microntroller with more on-chip RAM allowing for a real-time MP3 software decoder. The added USB interface allows file transfer with a personal computer.
+ 8KB
An upgrade to the LPC2138 microntroller, the LPC2148 substitutes Full-speed USB 2.0 device functionality for a slightly higher cost.

More Information


Working Prototype


DAC Circuit                                                       SD Card InterfaceSchematics

  • Audio Player

Example Code

  • Audio Player


This design example shows possible hardware and software techniques used to implement the design. It is imperative that the viewer use sound engineering judgment in determining the fitness of this design example for any particular application. This design example may include information from 3rd parties and/or information which may require further licensing or otherwise. Additional hardware or software design may be required. NXP Semiconductors does not support or warrant this information for any purpose other than an informational design example.

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