Olimex's USB-NeoHub Promises Perfect Compatibility with TinyUSB on the Raspberry Pi RP2040

Designed to work around a bug in either TinyUSB or the RP2040 — or both — this open-hardware USB 2.0 hub is guaranteed compatible.

Gareth Halfacree
2 months agoHW101

Bulgarian open source specialist Olimex has announced the release of a compact four-port USB hub, designed primarily as a means of working around a bug in TinyUSB running on a Raspberry Pi RP2040 microcontroller: the USB-NeoHub.

"The modern retro computer Neo6502's new firmware now supports USB flash drives and USB keyboards," Olimex founder Tsevtan Usunov explains of his latest design, referring to an open source retro-themed single-board computer he unveiled last year. "However, there seems to be an issue either with the [Raspberry Pi] RP2040 USB hardware or the TinyUSB [library]. When a USB keyboard is connected directly to RP2040, it works fine. However, when the keyboard is connected via a USB hub, there is a high chance it will not work."

As the Neo6502, which is based on a Raspberry Pi RP2040 microcontroller and a MOS 6502-compatible Western Design Center W65C02 CPU, has only one USB Type-A port that can now pull double-duties for both keyboard input and flash storage, that's a problem. "To add to the complexity," Usunov continues, "some keyboards work with any USB hub, and some USB hubs work with any keyboards. Unfortunately, in most cases, these cheap USB hubs, like the one we [sell] and many others, simply refuse to work. Out of the 10 USB hubs I bought to test, only two were functional."

Having discovered that he's far from alone in such a failure rate, Usunov set about finding a USB hub chip that would work all of the time — and, having tracked down such a beast, designed it into a compact four-port hub dubbed the USB-NeoHub.

"USB-NeoHub is 100% compatible with RP2040 USB and allows multiple USB peripherals to be connected to it," he says of the board, which supports USB 2.0 and USB 1.1 peripherals. "In the case of Neo6502, this includes a USB flash drive along with a USB keyboard."

The USB-NeoHub is now available to order on the Olimex website at €5 (around $5.40); as you would expect of an Olimex design, the hardware files have also been published to GitHub under the reciprocal GNU General Public License 3.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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