usb

659 Articles

Top side of the VL670 breakout board, with two USB connectors and the VL670 chip in the center.

A Chip To Bridge The USB 2 – USB 3 Divide

March 7, 2022 by 39 Comments

On Twitter, [whitequark] has  found and highlighted an intriguing design – a breakout board for the VL670, accompanied by an extensive yet very easy to digest write-up about its usefulness and inner workings. The VL670 is a chip that addresses a surprising problem – converting USB 2.0 signals into USB 3.0.

If you have a USB 2.0 device and a host with only USB 3.0 signals available, this chip is for you. It might be puzzling – why is this even needed? It’s about the little-known dark secret of USB3, that anyone can deduce if they ever have to deal with a 9-pin USB 3.0 connector where one of the three differential pairs doesn’t quite make contact.

When you see a blue “3.0” port, it’s actually USB 2 and USB 3 — two separate interfaces joined into a single connector. USB 3 uses two single-directional differential pairs, akin to PCI-E, whereas USB 2 uses a single bidirectional one, and the two interfaces on a blue connector operate basically independently of each other. There’s many implications to this that are counterintuitive if you simply take “USB 3.0” for “faster backwards-compatible USB”, and they have painful consequences.

For instance, USB 3 hub ICs have two separate hub entities inside – one for USB 3 and one for USB 2. Even if you have a USB 3 hub plugged into a USB 3 port, multiple USB 2 devices plugged into it still cannot break through the USB 2 uplink limit of 480 MBps. If you ever thought that a faster hub with a faster uplink would fix your USB 2 device speed problems – USB-IF engineers, apparently, thought differently; and you might have to find a workaround for your “many cheap SDRs and Pi 4 in a box” setup. Continue reading “A Chip To Bridge The USB 2 – USB 3 Divide” →

USB Temperature Logger With Some Extra Tricks

March 7, 2022 by 5 Comments

Many of us electronics hacker types tend to have at least the same common equipment on our benches, namely a multimeter, an oscilloscope, some sort of adjustable power supply, and maybe a logic analyzer. These are great tools covering many bases, but dealing with temperature measurements is often neglected. A sudden need for such often results in just buying a either dedicated measurement unit, or some cheap eBay thermocouple board and just rolling with a few hacks. [Jana Marie Hemsing] had a need for measuring the thermal side of things, and got fed up with hacking with piles of boards, and designed herself a proper instrument for the task.

The result is a very tidy four-channel thermocouple frontend, feeding the data into the host computer via USB. Each of the four channels can either be a K-type input or a NTC thermistor input, decided at board assembly time, but you could just build two units with four channels of each and cover all bases. The K-type thermocouple input is based around the MAX31855 series device. While the ‘KASA’ suffixed device is probably most common, if you need to dedicate some channels to handling one of the other six or so other common thermocouple types, that just needs the appropriate MAX31855 variant dropping in, and you’re good to go.

For the controller, [Jana] has chosen the common STM32F0x microcontroller, which handles all the USB protocol side of things. The extra functionality added allows direct driving of a heater controller via the DRV8837 H-Bridge, with a extra few open collector outputs for other things you might want to drive. This allows the logger to function as a kind-of thermal IO device. Firmware is written in good old fashioned STM32 HAL, using the standard STM32CubeMX and the GCC toolchain. It looks like the Makefile came via the STM32 Project Generator route. The firmware has a neat trick up its sleeve too; with a flick of the switch on the back, the firmware can switch between outputting CSV data over a standard USB CDC link (a virtual serial port), or it can present a SCPI terminal interface, enabling integration into existing SCPI-based test flows. Nice work!

We’ve seen a few logging projects on these fair pages, like this battery powered ESP32 logger device. If IoT logging is more your thing, here you go.

A Gameport Joystick To USB-MIDI Converter

February 24, 2022 by 1 Comment

These days, live music performance often involves electronic synthesizers and computers rather than traditional instruments played by hand. To aid in his own performances, [alekappa] built a special interface to take signals from a joystick and convert them to MIDI messages carried over USB.

The build is simple and straightforward, using a Teensy LC to interface with a simple gameport joystick. With a smattering of simple components, it’s easy to read the outputs of the joystick with only a little debounce code needed to ensure the joystick’s buttons are read accurately. Similarly, analog axes are read using the analog-to-digital converters onboard the microcontroller.

This data is then converted into control changes, note triggers and velocity levels and sent out over the Teensy LC’s USB interface. A mode switch enables changes to the system’s behaviour to be quickly made. The device is wrapped up in a convenient housing nabbed from an old Gameport-to-USB converter from many years ago.

It’s a neat project and we’re sure the joystick allows [alekappa] to add a new dimension to his performances on stage. We’ve seen other great MIDI controllers, too, from the knitted keyboard to the impressive Harmonicade. If you’ve got your own mad musical build under construction, don’t hesitate to drop us a line!

On the left, four through-hole USB-C connectors laid out on a purple cutting mat. On the right, a teardown picture shows that there's neither resistors nor CC connections inside such a connector, resulting in consequences described in the article.

The USB-C Connectors You Never Knew You Wanted To Avoid

February 20, 2022 by 24 Comments

On Tech Twitter, some people are known for Their Thing – for example, [A13 (@sad_electronics)], (when they’re not busy designing electronics), searches the net to find outstanding parts to marvel at. A good portion of the parts that they find are outstanding for all the wrong reasons. Today, that’s a through-hole two-pin USB Type-C socket. Observing the cheap tech we get from China (or the UK!), you might conclude that two 5.1K pulldown resistors are very hard to add to a product – this socket makes it literally impossible.

We’ve seen two-pin THT MicroUSB sockets before, sometimes used for hobbyist kits. This one, however, goes against the main requirement of Type-C connectors – sink (Type-C-powered) devices having pulldowns on CC pins, and source devices (PSUs and host ports) having pull up resistors to VBUS. As disassembly shows, this connector has neither of these nor the capability for you to add anything, as the CC pins are physically not present. If you use this port to make a USB-C-powered device, a Type-C-compliant PSU will not give it power. If you try to make a Type-C PSU with it, a compliant device shall (rightfully!) refuse to charge from it. The only thing this port is good for is when a device using it is bundled with a USB-A to USB-C cable – actively setting back whatever progress Type-C connectors managed to make.

As much as USB Type-C basics are straightforward, manufacturers get it wrong on the regular – back in 2016, a wrong cable could kill your $1.5k MacBook. Nowadays, we might only need to mod a device with a pair of 5.1K resistors every now and then. We can only hope that the new EU laws will force devices to get it right and stop ruining the convenience for everyone, so we can finally enjoy what was promised to us. Hackers have been making more and more devices with USB-C ports, and even retrofitting iPhones here and there. If you wanted to get into mischief territory and abuse the extended capabilities of new tech, you could even make a device that enumerates in different ways if you flip the cable, or make a “BGA on an FPC” dongle that is fully hidden inside a Type-C cable end!

Open Source LXI Tools Free Us From Vendor Bloat

February 18, 2022 by 8 Comments

LXI, or LAN eXtensions for Instrumentation is a modern control standard for connecting electronics instrumentation which supports ethernet. It replaces the older GPIB standard, giving much better performance and lower cost of implementation. This is a good thing.  [Martin Lund] has created the open source lxi-tools project which enables us to detach ourselves from the often bloated vendor tools usually required for talking LXI to your bench equipment. This is a partial rewrite of an earlier version of the tool, and now sports some rather nice features such as mDNS for instrument discovery, support for screen grabbing, and a LUA-based scripting backend. (API Link)

SCPI or Standard Commands for Programmable Instruments is the text-based language spoken by many instruments, allowing control and querying of an instrument. Just to be clear, SCPI is not at all a new thing, and older instruments that have GPIB or RS232 connectors, still could talk SCPI. lxi-tools is not for those. Some instruments can also be very picky about the formatting of commands, especially if they’re buggy, so the ability to interactively debug commands is very desirable. It is quite possible to make poor use of SCPI commands in your test script and end up with tests that just take far longer to execute that they need to. lxi-tools has a benchmarking tool too, which helps you to dig in and find out where all the time is going and make suitable adjustments.

We’ve not seen much about LXI on Hackaday, but we did cover using PyVISA for dealing with SCPI-over-GPIB in python.  If you have an older instrument  with GPIB and you don’t want to sell a internal organ to pay for a USB adaptor, here’s one you can make yourself.

Rainbow DIP Switch Is The Coolest Way To Configure Your Project

February 1, 2022 by 28 Comments

Oftentimes, when programming, we’ll put configuration switches into a config file in order to control the behaviour of our code. However, having to regularly open a text editor to make changes can be a pain. This colorful little DIP switch dongle from [Glen Aikins] makes for a fun alternative solution.

Do want.

The build is simple, relying on a rainbow-colored 8-pin DIP switch as the core of the project. A PIC16F1459 then reads the position of the switches, with the 8-bit microcontroller doing the job of speaking USB to the host machine. The device enumerates as a USB HID device, and reports to the host machine when queried as to the state of its 8 switches. [Glen] used a basic C# app to show a digital representation of the switches on screen changing as per the real physical DIP switch plugged into the machine.

It’s a great tool for controlling up to 8 different parameters in a program you might be working on, without having to dive into your editor to change the relevant parts. Also, it bears noting that the rainbow design is simply very fetching and a cool thing to have plugged into your computer. It’s a more serious device than [Glen’s] hilarious 4-byte “solid state drive” that we saw recently, but we love them both all the same!

Retro Gaming With Retro Joysticks

January 30, 2022 by 12 Comments

One of the biggest reasons for playing older video games on original hardware is that emulators and modern controllers can’t replicate the exact feel of how those games would have been originally experienced. This is true of old PC games as well, so if you want to use your original Sidewinder steering wheel or antique Logitech joystick, you’ll need something like [Necroware]’s GamePort adapter to get them to communicate with modern hardware.

In a time before USB was the standard, the way to connect controllers to PCs was through the GamePort, typically found on the sound card. This has long since disappeared from modern controllers, so the USB interface [Necroware] built relies on an Arduino to do the translating. Specifically, the adapter is designed as a generic adapter for several different analog joysticks, and a series of DIP switches on the adapter select the appropriate mode. Check it out in the video after the break. The adapter is also capable of automatically calibrating the joysticks, which is necessary as the passive components in the controllers often don’t behave the same way now as they did when they were new.

Plenty of us have joysticks and steering wheels from this era stored away somewhere, so if you want to experience Flight Simulator 5.0 like it would have been experienced in 1993, all it takes is an Arduino. And, if you want to run these programs on bare metal rather than in an emulator, it is actually possible to build a new Intel 486 gaming PC, which operates almost exactly like a PC from the 90s would have.

Continue reading “Retro Gaming With Retro Joysticks” →