A cable is just a cable. Unless it has a fully functional protocol analyzer built right in.
Many spacecraft and space instruments flying today depend on the SpaceWire protocol (ECSS-E50-12A standard) to provide reliable, high-speed communications. It is challenging to validate and debug SpaceWire systems within the physical confines and environmental extremes of these applications. That’s the mission of a new instrument-in-a-wire, a feat of electrical and mechanical engineering from Skylab Industries (Skylab).
The company’s engineers depended on the unified, automated Altium Designer environment to harness all the engineering disciplines required to get this product off the ground.
Skylab Industries flies high through collaboration
Skylab is a specialty engineering company based in
Skylab engineers come from many institutions all across Europe; “from research institutions or global industry leaders like AirBus and Air France, bringing us lots of experience and expertise,” says CEO Vincent Lavignolle.
The company focuses on R&D projects for the next generation of flight-borne systems. According to Lavignolle, “We specialize in challenging projects. With these projects, you can expect that the return on investment will be at minimum three years.”
“To pursue those goals, there are three keys to Skylab ‘s business model,” explains Lavignolle.” We need to have the best possible products, to be competitively priced and to maintain good margins. We are developing the model today – in three years we will have two or three generations of our products and the model will be fully realized.”
For an R&D-oriented company like Skylab, the process of moving from idea to successful products rests on collaboration among engineers and companies of many disciplines. The company’s core strength lies in intellectual property and collaboration of its electrical and mechanical engineers. Externally, Skylab plans to partner with additional international partners to apply its specialized solutions. “Our intention is to collaborate and co-operate more and more with these kind of companies,” states Lavignolle. “What is very important is to preserve a maximum of intellectual property and to be sure that we are doing the most effective activity we have to do for making a competitive product.”
A protocol analyzer in a cable
One of the most notable new products from Skylab is the
SpaceWire smartCable. It is a high-speed SpaceWire
bridge and analyzer molded into a USB-compatible
cable. It serves a three-in-one
purpose: a bridge between USB and SpaceWire, a protocol analyzer, and a physical
cable in itself.
SpaceWire is a recent protocol developed by the European Space Agency (ESA) to provide a high-speed link for spacecraft and space instruments up to 400 megabits per second in a reliable way. Widely used on many space missions by ESA, NASA and JAXA, SpaceWire supports high-speed links and networks for use onboard spacecraft, easing the interconnection of sensors, memories, processing units, and downlink telemetry sub-systems. SpaceWire links are serial, high-speed, bi-directional and full duplex. Application information is sent along a SpaceWire link in discrete packets, with control and time information being sent along SpaceWire links.
“SmartCable is a way for testing SpaceWire; it’s a bridge between USB and SpaceWire,” explains Stephan Davy, SpaceWire Technical Engineer. “The smartCable is a complete embedded system in a USB cable. It’s simplifying SpaceWire prototyping since you can plug either a laptop or a PC directly to the SpaceWire instrument.”
Multi-discipline effort needs multi-discipline tools
To develop unique products like smartCable, Skylab focuses on the core competencies that differentiate its products: electrical and mechanical engineering. The company outsources other disciplines, including software design and manufacturing, that are not part of its core R&D mission. In this way, the smartCable design is an example of coordination between engineering disciplines, and between contractors and subcontractors.
“The key difficulties in designing smartCable was strict area constraints on the PCB,” explains Davy. “That means we had to use the smallest chips available in the market. We also had to ensure mechanical solidarity of the board and the USB cabling, as well as compliance with USB speed and current constraints.”
FPGA-based design gave SpaceWire the flexibility and performance to meet these system performance specifications. According to Davy, “One of the obvious arguments of using an FPGA is that we can integrate more logical features. We actually needed two SpaceWire IP cores in the analyzer mode of the smartCable. We integrated a lot of logic modules that we need to control the analogue chips and to implement communications features.”
The unified design environment of Altium Designer simplified the multi-discipline design process for Skylab’s engineers, starting with design capture and PCB layout. “When we used the schematic and layout feature of Altium Designer, we were pleased by the way we could implement design goals and check that there were no errors of any kind before doing the layout. We also liked Altium Designer’s ability to place and move traces quite easily.”
When it was time for the electrical and mechanical engineers to collaborate, the unified design environment came into play. “We were also very interested by the bridges that Altium Designer provides us, such as the bridges between the FPGA constraints file and the I/O on the PCB on the one hand and the mechanical side on the other.”
These links were critical for spanning design domains and preventing errors from creeping in. “We needed to make sure that the PCB would fit within the strict mechanical constraints. The ECAD-MCAD link for mechanical design was important for the PCB. Mechanical considerations are a relatively important input to the constraints of our design, especially because of the location of the input of the power supply, and on the smartCable project in particular, the size of the connector was a huge constraint for us.”
The multi-discipline design environment simplified interaction with outsourced design and manufacturing resources too. For example, Davy mentions that Skylab’s contract layout partner also uses Altium Designer, so file sharing and compatibility is seamless.
3D visualization and auto-checking cast out errors
During mechanical engineering efforts, Skylab was able to employ visualization and error checking features that played a big role in first-pass manufacturing success. “We use the 3D visualization for checking the footprints and the packages. It is an excellent way for us to spot some minor errors.”
Visualization and auto-checking capabilities make a huge difference in speed and accuracy of the overall design process. “One key outcome of the design rule checking (DRC) is that we succeed on our first design with Altium Designer with absolutely no errors in the prototype,” Davy says. “I'm sure that’s not due to a random fact. We auto-checked the schematics many times. Because of the quality of the technology we could go in deep into the holes, using the DRC. At the same time, automatically generating reports, and avoiding manual checks, helped us to speed up the design process.”
It can be very difficult to speed up a design process if engineers encounter a steep learning curve when adopting new tools. That was not a problem with the smartCable project. “It was easier to move to Altium Designer,” says Davy. “The French Altium representative offered to help us do video training even before we invested in the tool. We became convinced that the training was a good starting point for electronics department in using such a system. Also, Altium’s technical support people were very reliable and efficient.”
“The Altium Designer tutorial was a great starting point to have at the beginning,” said Mathieu Salanave, another Skylab engineer. “It doesn’t give all the details, but all we need to start.”
“The great thing about Altium Designer,” summarizes Salanave, “is that there are all the needed disciplines for designing a project: the FPGA, the PCB and the mechanical. If there’s any problem the software helps us to spot it. The bridges between the disciplines, in which there could be sources of errors, is taken care of with software. There are many people in the projects and there are many separations between the disciplines. Altium Designer makes it simple for different people to share design data.”
How to have a successful product take-off
Pulling together all the disciplines and business partners is a key challenge with developing any high-technology product. According to Lavignolle, the design environment plays a fundamental role. “It's very important because one of the secrets to innovation and collaboration is to be sure that you have the best tool in your hands. That makes you competitive. You can reduce the design cycle and you enter a market with a great product.”
“If you have the right tools and you are effective with them, you enter the markets very, very fast,” explains Davy. “You have the maximum chance to be successful in the business.”
