Author: Arya Voronova

498 Articles

All About USB-C: High-Speed Interfaces

January 17, 2023 by 40 Comments

One amazing thing about USB-C is its high-speed capabilities. The pinout gives you four high-speed differential pairs and a few more lower-speed pairs, which let you pump giant amounts of data through a connector smaller than a cent coin. Not all devices take advantage of this capability, and they’re not required to – USB-C is designed to be accessible for every portable device under the sun. When you have a device with high-speed needs exposed through USB-C, however, it’s glorious just how much USB-C can give you, and how well it can work.

The ability to get a high-speed interface out of USB-C is called an Alternate Mode, “altmode” for short. The three altmodes you can encounter nowadays are USB3, DisplayPort and Thunderbolt, there’s a few that have faded into obscurity like HDMI and VirtualLink, and some are up and coming like USB4. Most altmodes require digital USB-C communication, using a certain kind of messages over the PD channel. That said, not all of them do – the USB3 is the simplest one. Let’s go through what makes an altmode tick. Continue reading “All About USB-C: High-Speed Interfaces” →

All About USB-C: Power Delivery

January 9, 2023 by 65 Comments

USB-C eliminates proprietary barrel plug chargers that we’ve been using for laptops and myriads of other devices. It fights proprietary phone charger standards by explicitly making them non-compliant, bullying companies into making their devices work with widely available chargers. As a hobbyist, you no longer need to push 3 A through tiny MicroUSB connectors and underspecced cables to power a current-hungry Pi 4. Today, all you need is a USB-C socket with two resistors – or a somewhat special chip in case the resistors don’t quite get you where you want to be.

You get way more bang for your buck with USB-C. This applies to power too; after all, not all devices will subsist on 15 W – some will want more. If 15 W isn’t enough for your device, let’s see how we can get you beyond.

Reaching Higher

USB-C power supplies always support 5 V and some are limited to that, but support for higher voltages is where it’s at. The usual voltage steps of USB-C are 5 V, 9 V, 15 V and 20 V ; 12V support is optional and is more of a convention. These steps are referred to as SPR, and EPR adds 28 V, 36 V and 48 V steps into the mix – for up to 240 W; necessitating new cables, but being fully backwards and forwards compatible, and fully safe to use due to cable and device checks that USB-C lets you perform.

A charger has to support all steps below its highest step, which means that 20 V-capable chargers also have to support 5 V, 9 V, and 15 V as well – in practice, most of them indeed do, and only some might skip a step or two. You can also get voltages in-between, down to 3.3 V, even, using a PD standard called PPS (or the AVS standard for EPR-range chargers) – it’s not a requirement, but you’ll find that quite a few USB-C PSUs will oblige, and PPS support is usually written on the label. Continue reading “All About USB-C: Power Delivery” →

All About USB-C: Resistors And Emarkers

January 4, 2023 by 21 Comments

If you’ve been following along our USB-C saga, you know that the CC wire in the USB-C cables is used for communications and polarity detection. However, what’s not as widely known is that there are two protocols used in USB-C for communications – an analog one and a digital one. Today, let’s look at the analog signalling used in USB-C – in part, learn more about the fabled 5.1 kΩ resistors and how they work. We’ll also learn about emarkers and the mysterious entity that is VCONN!

USB-C power supply expects to sense a certain value pulldown on the CC line before it provides 5 V on VBUS, and any higher voltages have to be negotiated digitally. The PSU, be it your laptop’s port or a charger, can detect the pulldown (known as Rd) because it keeps a pullup (known as Rp) on the CC line – it then checks if a voltage divider has formed on CC, and whether the resulting voltage is within acceptable range.

If you plug a device that doesn’t make a pulldown accessible through the CC wire in the cable, your device will never get power from a USB-C port, and would only work with a USB-A to USB-C cable. Even the smarter devices that can talk the digital part of USB-C are expected to have pulldowns, it’s just that those pulldowns are internal to the USB-C communication IC used. A USB-C port that wants to receive power needs to have a pulldown.

This part is well-known by now, but we’ve seen lack-of-resistor failures in cheap devices aplenty, and the colloquial advice is “add 5.1 kΩ resistors”. You might be afraid to think it’s so simple, but you’d be surprised. Continue reading “All About USB-C: Resistors And Emarkers” →

3D render of the badge programming adapter PCB

Supercon 2022 Badge Gets A Tinkering Helper Add-on

January 2, 2023 by 3 Comments

Are you one of the lucky ones to own a Hackaday Supercon 2022 badge? Would you like to make it even easier to program than it already is? [brokebit] has exactly the project you might’ve been dreaming of all along — it’s a Supercon 2022 Badge programming adapter. With pass-through for all badge pins, four buttons, a total of ten DIP switches and four LEDs, the sheer IO of this add-on makes good use of the badge’s expansion header. But that’s not all, as there’s a USB-UART converter accessible through a MicroUSB socket.

Using mostly through-hole components, this board won’t leave you digging through parts drawers for exotic buttons or pin headers; most everything is jellybean. The pass-through capability of the adapter means that other badge add-ons will be compatible and you can even use this adapter to debug them, with DIP switches helping you disconnect whatever onboard circuitry interferes. For instance, if you’re not looking for USB-UART functionality provided by the classic CP2102, the dual DIP switches are right there for you to disconnect it on the fly.

The board is 6 layers, but since the quoted price was the same as a 4-layer board, it made for a more comfortable layout. Want a refresher on the badge? Here you go, and here’s our write-up about it before Supercon. Hackers have been stretching the limits of what the 2022 badge can get done — here’s a punch card reader, for instance.

Steve showing a circuit built with spintronics blocks

Electronics Explained With Mechanical Devices

January 1, 2023 by 16 Comments

It can be surprisingly hard to find decent analogies when you’re teaching electronics basics. The water flow analogy, for instance, is decent for explaining Ohm’s law, but it breaks down pretty soon thereafter.

Hydraulics aren’t as easy to set up when you want an educational toykit for your child to play with, which leaves them firmly in the thought experiment area. [Steve Mould] shows us a different take – the experimentation kit called Spintronics, which goes the mechanical way, using chains, gears, springs and to simulate the flow of current and the effect of potential differences.

Through different mechanical linkages between gears and internal constructs, you can implement batteries, capacitors, diodes, inductors, resistors, switches, transistors, and the like. The mechanical analogy is surprisingly complete. [Steve] starts by going through the ways those building blocks are turned into mechanical-gear-based elements. He then builds one circuit after another in quick succession, demonstrating just how well it maps to the day-to-day electronic concepts. Some of the examples are oscillators, high-pass filters, and amplifiers. [Steve] even manages to build a full-bridge rectifier!

In the end, he also builds a flip-flop and an XOR gate – just in case you were wondering whether you could theoretically build a computer out of these. Such a mechanical approach makes for a surprisingly complete and endearing analogy when teaching electronics, and an open-source 3D printable take on the concept would be a joy to witness.

Looking for something you could gift to a young aspiring mind? You don’t have to go store-bought – there are some impressive hackers who build educational gadgets, for you to learn from.

Showing a USB-C tester running the DingoCharge script, charging a battery pack at 7V. To the right is a battery pack being charged, and a USB-C charger doing the charging.

Use USB-C Chargers To Top Up Li-Ion Packs With This Hack

January 1, 2023 by 5 Comments

In USB-C Power Delivery (PD) standard, the PPS (Programmable Power Supply) mode is an optional mode that lets you request a non-standard voltage from a charger, with the ability to set a current limit of your choice, too. Having learned this, [Jason] from [Rip It Apart] decided to investigate — could this feature be used for charging Li-Ion battery packs, which need the voltage and current to vary in a specific way throughout the charging process? Turns out, the answer is a resounding “yes”, and thanks to a USB-C tester that’s programmable using Lua scripts, [Jason] shows us how we can use a PPS-capable USB-C charger for topping up our Li-Ion battery packs, in a project named DingoCharge.

The wonderful write-up answers every question you have, starting with a safety disclaimer, and going through everything you might want to know. The GitHub repo hosts not only code but also full installation and usage instructions.

DingoCharge handles more than just Li-Ion batteries — this ought to work with LiFePO4 and lithium titanate batteries, too.  [Jason] has been working on Ni-MH and lead-acid support. You can even connect an analog output thermal sensor and have the tester limit the charge process depending on the temperature, showing just how fully-featured a solution the DingoCharge project is.

The amount of effort put into polishing this project is impressive, and now it’s out there for us to take advantage of; all you need is a PPS-capable PSU and a supported USB-C tester. If your charger’s PPS is limited by 11V, as many are, you’ll only be able to fully charge 2S packs with it – that said, this is a marked improvement over many Li-Ion solutions we’ve seen. Don’t have a Li-Ion pack? Build one out of smartphone cells! Make sure your pack has a balancing circuit, of course, since this charger can’t provide any, and all will be good. Still looking to get into Li-Ion batteries? We have a three-part guide, from basics to mechanics and electronics!

Showing the same thumbdrive plugged into the same USB-C port in two different orientations, enumerating as two different USB ports

Dirty USB-C Tricks: One Port For The Price Of Two

December 31, 2022 by 48 Comments

[RichardG] has noticed a weird discrepancy – his Ryzen mainboard ought to have had fourteen USB3 ports, but somehow, only exposed thirteen of them. Unlike other mainboards in this lineup, it also happens to have a USB-C port among these thirteen ports. These two things wouldn’t be related in any way, would they? Turns out, they are, and [RichardG] shows us a dirty USB-C trick that manufacturers pull on us for an unknown reason.

On a USB-C port using USB3, the USB3 TX and RX signals have to be routed to two different pin groups, depending on the plugged-in cable orientation. In a proper design, you would have a multiplexer chip detecting cable orientation, and routing the pins to one or the other. Turns out, quite a few manufacturers are choosing to wire up two separate ports to the USB-C connector instead.

In the extensive writeup on this problem, [Richard] explains how the USB-C port ought to be wired, how it’s wired instead, shows telltale signs of such a trick, and how to check if a USB-C port on your PC is miswired in the same way. He also ponders on whether this is compliant with the USB-C specification, but can’t quite find an answer. There’s a surprising amount of products and adapters doing this exact thing, too, all of them desktop PC accessories – perhaps, you bought a device with such a USB-C port and don’t know it.

As a conclusion, he debates making an adapter to break the stolen USB3 port out. This wouldn’t be the first time we’re cheated when it comes to USB ports – the USB2 devices with blue connectors come to mind.