Kicad:GPL PCB Suite

Kicad is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork.

Designed and written by Jean-Pierre Charras, a researcher at LIS (Laboratoire des Images et des Signaux) and a teacher in IUT de Saint Martin d'Hères.(France), in the field of electrical engineering and image processing.
Kicad is a set of four softwares and a project manager:

• Eeschema :Schematic entry.
• Pcbnew :Board editor.
• Gerbview :GERBER viewer (photoplotter documents).
• Cvpcb :footprint selector for components used in the circuit design.
• Kicad: project manager.

With the project manager, Kicad, you can choose or create a project and launch Eeschema, Pcbnew, etc. This electronic workbench is free of charges and is open source (GPL). It is useful for everybody working in electronic design (schematic diagrams and Printed Board up to 16 layers).

This software (using WXWIDGETS) is MULTI-PLATFORM. It is running under LINUX and Windows (XP or 2000), for which updates are regularly provided. Currently, the precompiled version of Linux has been tested using Mandrake 9.2 or 10.0 (works with 10.1).
Sometime the softwares are also been tested under other O.S., especially FreeBSD and Solaris.

(Source: http://www.lis.inpg.fr/realise_au_lis/kicad/)

EdSim51:The 8051 Simulator for Teachers and Students

Do you want to learn about microcontrollers and embedded systems? Are you studying the 8051 microcontroller? Do you want to test your code for communicating with peripherals without having to first build the hardware? Are you teaching an embedded systems course and would like your students to have access to a virtual 8051 training kit?

If the answer to any or all of the above is true, then you've come to the right place. The EdSim51 Simulator for the popular 8051 microcontroller is exactly the tool you need. And it's FREE!

A virtual 8051 is interfaced with virtual peripherals such as a keypad, motor, display, UART, etc. The student can write 8051 assembly code, step through the code and observe the effects each line has on the internal memory and the external peripherals.

The Virtual Peripherals:

• Analogue-to-Digital Converter (ADC)
• Comparator
• UART
• 4 Multiplexed 7-segment Displays
• 4 X 3 Keypad
• 8 LEDs
• DC Motor
• 8 Switches
• Digital-to-Analogue Converter (DAC) - displayed on oscilloscope

Why EdSim51's Simulator and not some of the many other simulators that are available?
Many of the simulators for the 8051 that you will find are industry-standard. They are used by professional 8051-based embedded udent can learn how to scan a keypad, multiplex 7-segment displays, control a motor asystems designers. While they show the state of the registers, memory and the port pins while code is being debugged, they do not have graphical representations of peripherals that can be used interactively to communicate with the 8051. EdSim51 have filled that need. The stnd count its revolutions, etc.

Download EdSim51 here.

(Source: http://www.edsim51.com)

Sonnet Lite

Sonnet Lite Version 11.53 is a free feature-limited version of Sonnet's professional Sonnet Suite, which provides EM analysis to hundreds of companies across the globe. Many major manufacturers of high-frequency components and boards depend on Sonnet to analyze their predominantly planar high-frequency designs from 1 MHz through several THz. You can download it right now - it's FREE!

Key Benefits of Sonnet Lite

• Most accurate, reliable planar EM software in the world
• Easy to learn with clear tutorials and online help
• Fast and efficient
• It's Free!

(Source: http://www.sonnetusa.com/products/lite/)