Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/q-and-a-session-on-luna-hardware-connectivity

Hi, friends!

As community manager for Great Scott Gadgets, one of my favourite tasks is finding answers to questions that come in through email, Twitter, GitHub, and Discord. Thankfully you all are great at asking questions, especially about the USB Type-C connectors on LUNA! In this blog post Michael Ossmann responds to most of the USB Type-C queries I’ve received (and asked) about LUNA in the last few weeks.

Community Question: Old pictures of LUNA feature Micro-USB connectors but the latest pictures show USB Type-C connectors. Why the change?

Kate’s original LUNA design used Micro-USB connectors, but we decided to switch to Type-C connectors a couple of revisions later. Based on the USB specification, Micro connectors may be the best choice for LUNA, but I don’t know anyone who actually likes them. They can be difficult to insert properly and they are less reliable than other USB connectors. Maybe the best thing about them is that the cable that tends to wear out and not the receptacle.

Straithe Question: So other than likeability, are there other reasons USB Type-C connectors were chosen?

Type-C connectors are more robust and easier to insert than Micro-USB, particularly since they function when inserted in either orientation. They have become quite common, so we think folks are likely to already have cables. Significantly, Type-C is the only connector specified for the recent USB 3.2 and USB4 standards, so we see it as the most future-proof option in regards to cable acquisition.

Straithe Question: Were there any concerns about switching to USB Type-C connectors?

Our biggest concern about switching to Type-C connectors was that it might give a false impression that LUNA supports SuperSpeed USB, often referred to as USB 3.0. We’ve noticed more and more USB 2.0 devices with Type-C connectors over the past couple years, so our hope is that few people would be confused by this.

Type-C connectors also cost more than Micro connectors, which was an important consideration for us since there are three of them on LUNA. One of the ways we have tried to make LUNA accessible is by making it affordable. Fortunately, we were able to find USB 2.0 Type-C connectors that cost less than USB 3.0 Type-C connectors that include SuperSpeed signals.

Community Question: Will LUNA be able to support SuperSpeed with software changes?

No. A Type-C connector can be used on a USB 3.0 device for SuperSpeed, but it can also be used on a USB 2.0 device such as LUNA at Low-speed, Full-speed, or High-speed. Although the LUNA software framework includes some experimental support for SuperSpeed USB on alternative hardware platforms, the LUNA hardware platform is a low-cost device supporting only USB 2.0 speeds.

Straithe Question: You’ve mentioned a number of different USB speeds. To recap, what are the different USB speeds and what USB versions do they line up to?

There are four speeds in the USB 2.0 and USB 3.0 specifications:

(Additionally there are extensions of SuperSpeed in USB 3.1 and above.)

Although the USB 2.0 specification updates previous specifications and includes both Low-speed and Full-speed, a lot of folks refer to High-speed USB as “USB 2.0”. Similarly, people often refer to SuperSpeed USB as “USB 3.0”, even though it can be found in various versions of the specification higher than 3.0. The USB 3.0 specification supplements USB 2.0, adding SuperSpeed signals on additional wires while following the USB 2.0 specification on other wires within the same cable.

Community Question: Does LUNA come with any cables?

Partly because of our switch to Type-C connectors and partly to save cost and packaging, we have decided not to include cables with LUNA. One of the reasons for this is that it is difficult to predict what cables folks will need for different applications. As an illustration, I used LUNA recently in-line on a connection between a PC and a HackRF One. This required four cables:

• A-to-C cable between the PC and LUNA’s Target C port
• A-to-Micro between LUNA’s Target A port and the HackRF One
• C-to-C cable between my laptop and LUNA’s Host port
• A-to-C cable between my laptop and LUNA’s Sideband port for programming

This particular selection of cables depended on the available ports on the laptop, the PC, and the HackRF One. In order to accommodate most of the combinations we anticipate, we would have to include at least half a dozen different cables, making LUNA needlessly expensive and its packaging overly bulky. Instead we decided to keep LUNA small and affordable by relying on LUNA users to acquire their own cables for their individual needs.

Community Question: Does LUNA pass through SuperSpeed signals when used as a USB analyzer?

To use LUNA as a USB analyzer, you use one cable to connect a USB host to LUNA’s “Target” Type-C port and another cable to connect a USB device to LUNA’s “Target” Type-A port. Both of those ports on LUNA are USB 2.0 connectors, so they only pass through the USB 2.0 data signals. LUNA does not pass through SuperSpeed signals or any of the ancillary signals supported on some Type-C devices such as those used for Power Delivery (PD) communication.

Community Question: I guess LUNA doesn’t have any PD capabilities then?

Although we don’t pass Power Delivery signals through LUNA, the hardware is designed to have some ability to transmit and receive PD signals:

We added these capabilities to the hardware design when switching to Type-C connectors, but we currently do not have a plan to implement gateware for PD. If you have a specific use case for which you would like software support, please let us know. At a minimum it will be possible to implement your own PD solution in nMigen. Note that LUNA’s Type-C ports are not tolerant of voltages above USB’s standard 5 V, so some PD experiments could put your LUNA in danger of overvoltage.

For more sophisticated PD testing and experimentation, including passive monitoring, I recommend checking out Rod Whitby’s USB-PD Add-On for Glasgow currently in development. Rather than adding similar circuitry to LUNA (and making LUNA larger and more expensive), we think this is a great application for a special-purpose design such as Rod’s board.

Community Question: Does LUNA support any USB Alternate Modes?

LUNA’s hardware design also permits 3.3 V I/O on the SBU1/SBU2 signals of all three Type-C connectors. This should enable experimentation with some lower speed Alternate Modes such as those used by some serial debuggers, but it will not support video modes.

Straithe Question: Thank you for answering our questions today. Do you have any last comments?

Thanks for curating these great questions! I just want to give a big thank you to everyone who is supporting LUNA on Crowd Supply. We truly appreciate each and every one of you!

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/luna/updates/a-look-at-current-progress-on-lunas-case-and-a-contest

Background

Initially, we planned on creating a laser-cut acrylic enclosure for LUNA. We had started sketching out a design when Michael Ossmann saw the beautiful design work Timon of Diodes Delight did on the milled aluminum case for Glasgow. Mike contacted Timon right away to ask for his design help as we knew a milled aluminum case would be a high quality option, more durable and protective than our original layered acrylic idea. Soon after, Timon accepted our request and started working on a case.

Progress

We have worked with Timon on the case design over the past few months, which has been a delight. He did a nice job of shaping the interior to maximize mass and give the case a comfortable (yet light) weight while still accommodating all of LUNA’s components. Timon even found light pipes that suit LUNA’s tightly spaced LEDs, which are less than 2 mm apart! Recently, Timon sent us the following 3D renders, and we knew we had our design.

A little over two weeks ago we approached our manufacturers with the case design to get the first prototypes made. In the time since the campaign launched, we have received pictures of the freshly milled top pieces of the enclosure.

Once milling is finished, these prototypes will be sandblasted, anodized, and laser etched. Sandblasting will remove the tool marks from the interior of the cases, anodizing will coat the aluminum and turn it black, as shown in the 3D renders. Laser etching will add the labels, GSG markings, and other symbols to the case.

We really look forward to receiving these prototype cases soon, testing them, and uploading pictures/updates for you shortly after!

Today marks the day that our campaign to fund LUNA launches on Crowd Supply! Over the next six weeks (from July 15th to August 26th) anyone will be able to pre-purchase a LUNA and support our goal of bringing this low-cost multi-tool for building, analyzing, and hacking USB devices to market. If you want to learn more about LUNA, we have a detailed writeup of the device on our Crowd Supply campaign page that we hope you will read!

In this interview, Michael Ossmann visits Adafruit in New York and chats with Limor “Ladyada” Fried about GreatFET and HackRF. The two talk about what GreatFET neighbours are, how to design GreatFET neighbours, and Mike demonstrates how to use a wiggler to separate neighbours from a GreatFET. This is followed up with a short discussion on HackRF and Portapack and how they work together.

October 2020

Kyle Kaminky from Arvada, Colorado emailed us in October to ask for a HackRF One. He’s an EE with a young family who told us, “After becoming familiar with my HackRF One and GNU Radio, I hope to use it to begin making tutorials on wireless communications and other RF topics. I picture a series of follow-on classes to Michael Ossmann’s DSP course. I would also enjoy getting enough experience and expertise to be able to write my own GNU Radio blocks and post them online for others to use to aid in their SDR projects. Ultimately I want to get others excited and informed about SDRs and the awesome things they can do.” He also told us to hold him accountable, so let’s have an update, Kyle.

November 2020

For November, we sent a handful of Throwing Star LAN Tap Kits to Bobby Dominguez in New Mexico because he wants to learn about networking and soldering.

December 2020

James is a teenager in Australia who is really interested in experimenting with RF and hacking embedded devices, so we sent him a YARD Stick One.

July 2020

Anna from South Carolina had a lame quarantined birthday in July, so we sent her a present- a GreatFET One. She recently started taking cybersecurity classes and wants to learn about hardware hacking.

August 2020

Ed from the Suffolk County (NY) Radio Club wrote to us in August to ask for free stuff for learning activities with their new members, mainly scouts and their parents. We sent a bunch of Throwing Star LAN Tap Kits, and hopefully they’ll be able to get together to use them soon.

September 2020

Axell Macclawd is a security researcher in Brazil. He requested a HackRF One for his project developing open source equipment and techniques to fight cargo theft and protect drivers, a large problem in Brazil. Drivers are held hostage and sometimes killed by thieves who use jammers to thwart the transportation companies’ GPS and GSM trackers. Axell’s goal is to prevent more loss of life.

April 2020

Dave Ferguson of the Woodinville (WA) Emergency Communications Team asked us for a HackRF One in April. This volunteer ARES group is turning a donated fire department aid truck into a mobile communications center that will service local public events (runs, bike rides, etc.) as well as provide essential communications via ham radio during emergencies. Their new HackRF One will allow them to watch communications across the entire spectrum and to potentially automate their systems.

May 2020

We sent a couple of YARD Stick Ones to the MCH2021 Badge Team. We can’t say any more than that, other than they are planning to make something really cool. And we sure are looking forward to 2021 and in-person hacker camps!

June 2020

Tim Fogle had some Good Ideas in June, so we sent him a GreatFET One. He wants to build a neighbor for CTF challenges.

January 2020

The Free Stuff recipient for January was Gabriel Sheeley, who runs an electrical engineering/embedded software meetup in Columbus, Ohio. They do do everything from soldering workshops, to tearing apart smart TVs, to automating chicken coops to keep out raccoons. Gabriel asked for a YARD Stick One to use in a talk about RF hacking, and now that the meetup is remote, the group will have to take turns with their new gadget.

February 2020

We sent a HackRF One to the CU Boulder Sounding Rocket Lab Avionics Team for their ground station. They told us that they are “building an 18-foot-tall rocket from scratch (all student-built) that will leave this humble planet for a brief period of time, before drifting gracefully back to earth and our eagerly waiting hands. We intend to shatter the records for collegiate and amateur rocketry at our upcoming launch later this year. Our most up-to-date simulations project a maximum altitude of 190km and speeds topping out at Mach 7. During the entire flight we aim to maintain contact with the vehicle so we can continuously monitor its physical (and emotional) state.”

We are looking forward to attending the launch, hopefully in 2021.

March 2020

In March, Luis Salha asked us for a YARD Stick One to use for RF encryption research for his current Swiss army knife project BlackBox. He says he’s been experimenting with RF capture, analysis, replay, and brute force attacks, and he hopes to learn more about key rolling/hopping and cracking keeloq encryption using readily available hardware.

September 2019

In September, we gave Chuck McManis a GreatFET One to experiment with. He owes us an update!

October 2019

Paul wrote to us from his shed in County Kildare to ask us for a few Throwing Star LAN Tap Kits to teach his kids how to solder.

November 2019

Way back in the Before Times, the organizers of the WOPR Summit 0x01 asked us to contribute a couple of GreatFET Ones for a hardware hacking booth. They planned to let attendees use the GreatFET Ones to run through some hands-on demos, then give them to the most passionate experimenters. That was a GreatPlan, but sweeping gesture. They are hoping to have a virtual event sometime in September 2020.

December 2019

Daniel Valdez, a student from Mexico City, requested a YARD Stick One. He is working on the development of a communication system through a router that sends a series of packets to an embedded system in order to automate control of devices in the home. He also wants to test the security protocols in the transmission of data from the different devices connected to the router.

Daniel Valdez, un estudiante de la Cuidad de México, solicitó un YARD Stick Uno. Está trabajando en el desarrollo de un sistema de comunicación por medio de un rúter que envía una serie de paquetes a un sistema embebido para poder tener el control de una casa por medio de domótica. Él también quiere probar la seguridad para establecer los protocolos de seguridad en lo que es la trasmisión de datos de los diferentes dispositivos comunicados con el rúter.

Last month, Kate Temkin began her blog series aimed at comparing FPGA families that have open source toolchains available. In the first post she reviews the pros, cons, and features of the Lattice iCE40 LP/HX, Lattice iCE40 UltraPlus, and Lattice ECP5 families.

Excerpt:

“The world of FPGAs has traditionally been full of closed-source mysteries: designs have long been crafted using expensive, multi-gigabyte vendor tools, and the inner working of vendors’ hardware and software have remained closely guarded secrets.

This changed when Claire Wolf created her IceStorm project, which reverse engineered Lattice’s low-cost iCE40 FPGAs, and led to an expansive ecosystem for creating FPGA designs using entirely open-source tools. Today, open-source toolchains exist targeting a handful of FPGA families; and a huge swathe of compatible FPGA hardware exists.

In this series, I’ll ‘show off’ a variety of hardware you can use to develop your own designs using open-toolchains– and hopefully help people to get a feel for the ecosystem.” Read the full post here.