I've been meaning to write an article regarding Radionics' Schematic Capture and PCB Layout tool:
Designspark.
Designspark is a free EDA (Electronics Design Automation) tool, which can be used by professional electronic engineers to hobbyists and students. You have to register to access all the features of the package, which is only a minor disadvantage. Unfortunately you have to do this every time you upgrade to the latest version.
When I started working in Ircona back in 2006, I got used to Cadence's Allegro HDL package. This is a top end software package with many advanced features. Allegro HDL is a powerful tool and easily allows the importing from other EDA design packages like OrCad. However I found it large and cumbersome when it came to smaller designs and I went in search of other design tools. We only had the one PCB Layout licence in the company and I never got an opportunity to try it out. However, I can compare the schematic capture side of things and detail my experiences in PCB Layout.
I've been using Designspark in Coolpower Products for the last two years. I've seen quite a few changes from version 5.0 of the software to the current version 7.0. I have personally designed and built either by hand or machine assembled through manufacturers more than 10 different designs of varying complexity from low voltage DC double sided 20mm x 40mm boards to 200mm x 100mm 4 layer boards to High Voltage AC (~240VAC @ 16A) 500mm x 400mm 2oz Copper designs, which are all now viable and functioning products. The tool may not be the best of the best, but it is great for what you get.
Schematic Capture
The schematic capture is straight forward enough. Select a component from the add component button (conveniently shaped like a transistor) and you can access all your component libraries.
Libraries
Libraries are bread and butter of schematic capture and layout. These contain all your details for components and layout files. The libraries in Designspark are split up into three seperate sections: Schematic Symbols, PCB Symbols, Components and 3D View. The Components join the Schematic Symbols and the PCB Symbols together to give a unique component to be placed. To create a new component, first you must create a schematic symbol, for example a square with 4 connections on the left and 4 on the right. As per most schematic design, the standard is to keep all inputs on the left, outputs on the right, power to the device on top and ground on the bottom.
Once this has been completed, you must create the PCB symbol. The PCB symbol should match the specific part you want in your design. A lot of the time, there is a standard PCB footprint that can be used and re-used, for example Fairchild's Wide SOIC-8 on the left hand side. This is a standard package size for small I2C devices like EEPROMS, RTC and other sensors.
Once the PCB symbol has been created, the Component can then be created joining these two parts together, linking the schematic with the PCB Layout.
At first I used Designsparks own libraries, but upon my first PCB, I found a lot of issues with pad sizes and incorrect connections on some of the devices. So I proceeded to create all my own libraries. Now this is not an ideal option and takes a lot more time, but it means that I have individually created each and every part and can prove each one is correct. This is advantageous in the long run if you want to use this tool professionally and want to reduce risks to layout.
PCB Layout
So you've created your schematic and that;s great on paper, but we want to make it into something real now. The PCB Layout tool comes included as part of the package and your schematic becomes a reality just by clicking "Translate to PCB". This opens up a very easy to use wizard, which guides you through some of the basic setup needed to get you started on the layout of your design. Unfortunately making a mess up at this point, is only really easily fixed by starting all over again, for example choosing 2 layer board, when you need a 4 layer board.
Autorouter
This is a standard autorouter, there's nothing special about it. It can be handy for trying to get an idea of the routing difficulty, but in the end, I prefer to hand route each and every signal. This may be more time consuming, but it increases my confidence in every signal.
File Outputs
The most important thing any designer or hobbyist wants, which Designspark easily provides are the following:
- Gerber Files (most common format is RS-274X or the older RS-274D)
- Excellon Drill Files
- BOM Files
- Component Positions (TXT and CSV Format)
These are the basic files that will get you your PCB laid out, components purchased and assembled through pick and place manufacturing process,
There are plenty of other file outputs that are very useful as well: Generic Netlist, Schematic PCB/Check, Dangling Tracks, Component Height and many more.
I would recommend using any Gerber viewer to verify your gerber files before sending to manufacturing. Gerbv is very popular.
Quick Note on the latest Designspark 7, they changed the output format of the Excellon Drill files from trailing zeros to leading zeros. I found this causes a problem with the scale of drill files, which affects 50% of the gerber viewers out there. Just open the .drl file and change the following:
METRIC or METRIC, TZ
to
METRIC,LZ,000.000
Revision Control System
Version Control is very useful for any engineer, hobbyist or student. The ability to not only save and improve on your design, but to be able to verify changes between any versions and to be able to undo changes from a repository are incredibly useful. With the ability to store large amounts online, it is a great idea to back up your design on any online repository .
I've proven Designspark works well in a repository situation. I have separate repositories for my libraries and each design. This allows me to backup my designs as well as allow any approved user to download and use my design if they so wish.
I've found BitBucket is very useful for this as it keeps any work online private by default, where as Git is public by default and you have to pay to keep it private
Conclusion
So I've discussed a number of points about Designspark and it's uses. I've written up a few pros and cons below, which can give you a quick run down of the program itself.
PROS:
- Obviously it's free for everyone. No worrying about licencing.
- The PCB Layout package comes immediately with the tool and is immediately ready to go.
- There's no awkward setup upon installation to get it just to work (obviously you can adjust it to your preferences if you so wish).
- Modelsource, there's a wide variety of libraries (schematics and layout) that come with the tool already that link to Radionics website, which easily gives you pricing and availability.
- The Tech support from Radionics for the tool are actually very quick and helpful. Although a little arrogant to make the necessary changes to fix the problem in the first place.
- Components in Libraries can be used to store all useful information on part, most importantly the manufacturer name and manufacturer order number for BOM generation.
- I found it very easy to get it up and running and start designing immediately compared to other CAD tools.
- There are numerous step by step wizards, which guide you through symbol creation, pcb translation and others. This saves time by using commonly used variables instead of hand drawing each time.
- You can use 3D View to view your design in a 3 Dimensional view and get an idea of how close components are and ease of building the board yourself (not covered in this review)
CONS:
- Have to re-register everytime a new version is released. Older versions are not removed.
- No offpages in schematic capture, difficult to keep track of where signals connect to on other pages. Can become very annoying as design grows.
- Modelsource, I know I've put this as an advantage above, but the disadvantage here lies in the trust that the libraries and parts are correct. But this can be ignored and you can create all of your own symbols by hand.
- The creation of schematic symbols and pcb symbols can be a little quirky and often lines don't meet up correctly due to grid alignment.
- There are plenty of little bugs and glitches in the program, but they are gradually getting weeded out over time.
- Solder Resist mask is not automatically added in PCB generation.
- Spacings are restricted to only Tracks, Pads, Vias, Shapes, Text and Boards. This makes it very awkward when you need specific design rules between specific signals and specific shapes.
Here's a list of interesting and useful website for your own designs:
- http://www.4pcb.com/gerber-file-guidelines.html
- https://www.apcircuits.com/resources/information/gerber_data.html
Don't forget to check out my latest PIC n' MIX article in Everday Practical Electronics, where I will show you how to build your own PICmas Tree, using the LPLC board from MJH Designs. I use 68 LEDs to make a festive looking LED tree that sparkles and glows for the festive season!
