Greg Cormier's Minicoralbridge Gets a Coral Mini PCI Express Accelerator Running in a Desktop
Filling a gap in the Coral ecosystem, this passive board adapts a mini-PCIe Coral Edge TPU accelerator for a desktop's full-size PCIe slot.
Maker Greg Cormier has come up with a simple open-hardware device which lets you take a Google Coral mini-PCI Express machine learning accelerator card and put it in a desktop computer's full-size PCI Express slot: the minicoralbridge.
"The goal was to try and learn a bit more about PCI [Peripheral Component Interconnect]," Cormier explains of the passive adapter board. "This card allows me to use my mini PCI Express Google Coral card in a regular PCI Express 1x slot."
Google launched the Coral range of on-device machine learning acceleration hardware four years ago, taking the Edge Tensor Processing Unit (TPU) the company had made and making it more accessible to developers outside the company. A USB accelerator and a system-on-module with carrier board were followed by additional models including a mini-PCI Express board aimed at single-board computers and laptops — but mechanically incompatible with most desktop systems.
Those whose desktops include M.2 slots and who wanted the increased performance available from a PCI Express interface rather than USB have the option of picking up A+E-key and B+M-key M.2 variants of the mini-PCIe accelerator — but for anyone lacking M.2 slots, or whose slots are already in use for NVMe storage or Wi-Fi radio modules, it was USB or nothing.
That's where the minicoralbridge comes in. A simple passive adapter, the bridge accepts an unmodified Coral Mini PCIe Accelerator — or any other mini-PCIe card which runs on a 3.3V feed and uses PCI Express as its exclusive communication method — and mechanically adapts it to a single-slot full-size PCI Express card.
"These are kits that you must solder yourself," Cormier says of the bundles he has begun to sell. "It can be done with a soldering iron easily enough with plenty of flux. It includes: 1 PCB with gold-plated edges; 1 mini-PCIe connector; 2 stand-offs."
The minicoralbridge kit is now available on Cormier's Tindie store for $8, with KiCad project files published under an unspecified open hardware license on GitHub. The Coral Mini PCIe Accelerator, meanwhile, is be available in the channel at $24.99 via links on the Coral website.