Audio Manipulation And Buffers using DSP-BF533 EZ-KIT Lite Dr. Veton Z. Këpuska By Husain Alotaibi Ahmed Alalyak ECE 3551 Microcomputer System I Spring 08

Introduction  Audio Manipulation through  Changing the gain  Introducing a delay  Using Low and High Pass Filters (FIR)

Implementation Scope  - without any push button pressed the audio is transmitted to the speakers with no modification  pressing PF8 will increase the volume of the audio and  LED 1 will be on when the volume is in the first step  LED 1+2 is lit and so on up to LED 5 then it resets  Pressing PF9 will decrease the volume of the audio and  Corresponding to the value of the current volume a specific range of LED’s will be lit to indicate the volume level  Further pressing will decrease the number of lit LED’s until it resets

Implementation Scope  Pressing PF10  Activates chorus effect and lit LED 3  Activates Low Pass filter and Lit LED 4  Activates High Pass Filter and lit LED 5  Fourth press will reset to default mode  Pressing PF11 will change the spanning with each press until it resets

Preparation  SW9 pins are all on  Initialization and enabling the six LED’s and the four Push Buttons

Interrupts used System Interrupts Defined Core Event NameDescription (Comments) SPORT0_RX_ISRIVG 9 DMA 1 Interrupt (Sport0 RX ISR  IVG 9) FLAG A_ISRIVG 12 Programmable flags Interrupt A (FlagA ISR  IVG 12) Timer0_ISRIVG 11 Timer0 (ISR  IVG 11)

Process processor start at main() in main.c. This program calls a various initialization routines to set up the EZ-Lite boards in a configuration that is needed for audio input/output, then it executes an infinite loop.

Process (continue)  This program is an interrupt driven program which means that the computer program only does something when a hardware interrupt is generated.

Process (continue)  File Process_Data will contain the user computational functions  In ISR functions will facilitate calling the computational functions and give their output

Effects and implementations  simple operation that can be performed in a DSP on an audio signal to create a volume control  Audio Panning Control uses gain to create a phantom source by varying the gain.

Chorus  Implementation of buffers to create a delay  The buffer will be used to read and write values each sample period, and incrementing to the next memory location for each sample.

Filters  Using MATLAB, we designed two filters and imported their coefficients.  used a circular buffer method to compute the output signal.

Issues  Much significant complication and problems are with the quality of the audio  Noise is the dominant problem in this project

Results & Conclusion  Successful development of an acceptable approach to implement popular audio effects  The board offers a broad usability in different fields  Appreciating this encouraging class