29. September 2011 by admin.

Get it now at http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2680&dDocName=en023592

The Noise Suppression Library is written almost entirely in assembly language. It is highly optimized to make extensive use of the dsPIC DSC device DSP instruction set and advanced addressing modes. The algorithm has been implemented keeping in mind the need to avoid data overflow. The library functions can be easily called by the user application through a well-documented Application Programmer’s Interface.

The noise suppression function removes noise from a 10 ms block of 16-bit speech data sampled at 8 kHz. This function is primarily a Frequency Domain algorithm in which a Fast Fourier Transform (FFT) is performed on each 10 ms block of data to analyze the frequency components of the signal. Thereafter, a Voice Activity Detection (VAD) algorithm is used to determine if the signal segment is speech or noise. The noise suppression algorithm maintains a profile of the noise and updates it every time a noise segment is detected by the VAD. Every frequency band of the input signal is then scaled according to the proportion of noise contained in that frequency band, thereby causing a significant degree of noise suppression in the resultant signal. The Algorithm thus adapts to changes in the nature and level of noise and does not require a separate noise reference input.

Features

Key feature of the Noise Suppression Library include:

• Simple user interface – only one library file and one header file

• All functions called from a C application program

• Full compliance with the Microchip C30 Compiler, Assembler and Linker

• Highly optimized assembly code that uses DSP instructions and advanced addressing modes

• Comprehensive API provides parametric control of the Noise Suppression Engine

• Noise reduction level can be controlled from 0 dB to 44 dB

• Audio Bandwidth: 0-4 kHz at 8 kHz sampling rate

• Library delivered on CD, which also includes:

o Several sample .wav files that incorporate different types of noise components

o User’s Guide

o Sample demo application with complete source code

Resource Requirements

Computational Requirements: 3.5 MIPS
Program Flash Memory: 8 KB
RAM: 1 KB

This library is available for free download and there are no associated royalties for this library

Posted in Software, Assembly, Software Stack, 16-bit, dsPIC | Print | 1 Comment »

3. April 2010 by admin.

From http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2680&dDocName=en544475

The Microchip Graphics Display Designer (GDD) is an MPLAB IDE plug-in and a visual design tool that provides customers with a quick and easy way of creating graphical user interface (GUI) screens for embedded applications on Microchip MCUs. The GDD is a design tool created for use with the Microchip Graphics Library.

For customers who are familiar with MPLAB IE, PIC MCUs, Microchip Graphics Library and MPLAB C Compilers, the GDD simplifies coding for the GUI screens. Customers can draw, move, resize, and delete screen objects, create multiple static screens, assign an LCD controller, select graphics-related configurations, and generate output source files. These source files can be compiled with the Microchip Graphics Library using the Microchip C compilers for PIC24, dsPIC and PIC32 MCUs.

GDD eliminates the need to manually calculate the X/Y coordinates for on-screen object placements. Nearly all the graphical objects (widgets) from the Microchip Graphics Library are supported in GDD.

GDD provides “what you see is what you get” results by using the same rendering code from the Microchip Graphics Library to draw objects on the PC screen. This guarantees that what you see on the PC screen is what you get on the target embedded screen.

Graphical resources can be imported into GDD for application development, including custom fonts and bitmap images. Various Microchip Graphics Library configuration settings can be set in GDD, including display resolution, color depth, LCD driver, etc. Code generation feature generates ANSI C code for PIC24, dsPIC and PIC32 MCUs. The code generated by this plug-in can be compiled with source files from the Microchip Graphics Library developed for Microchip’s PIC24, dsPIC and PIC32 MCUs.

Advanced users still have the option to call APIs from the Microchip Graphics Library directly without using GDD. This provides a finer control over the flow and behavior of the application.

Released version: 2.0.0.9c – Supports Windows XP, Windows Vista, Windows 7 (dated 09/17/09)

The GDD v2.0.0.9c works with Graphics Library v1.75b only, and not with the newer Graphics Library v2.00 or later.

To download Graphics Library v1.75b, click here to download.

Posted in Software, Graphics, Free Stuff | Print | 1 Comment »