Dev Kit Weekly: GroupGets LLC ORANGECRAB-R0D2-85
April 07, 2023
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FPGA-based designs are all the rage these days thanks to the flexibility provided by their customizable nature, and the ORANGECRAB-R0D2-85, created by Digital Systems Design Engineer Greg Davill and manufactured by GroupGets LLC, highlights the appeal of programmability.
The ORANGECRAB-R0D2-85 is a development board built around a Lattice ECP5 series 12Mbit FPGA, generally classed as a low-power, midrange FPGA. The ORANGECRAB features 84K Look Up Tables alongside 3744Kb of embedded block RAM, 669Kb of distributed RAM, and 128Mbit QSPI Flash memory. There’s also an additional 1Gbit of onboard DDR3L memory and a microSD card slot with a 4bit SD interface for any needed extra storage.
The development board also features a 12Mbit Micro USB port that connects directly to the board’s FPGA, a 48MHz oscillator, a standard 0.05” JTAG connector, four PLLs, and 20 I/O headers that you can program to be whatever you need. The ORANGECRAB utilizes high efficiency DCDC for main power supply, but it also includes a 100 milliamp (mA) battery charger and a lithium-polymer battery connector.
For programming, the ORANGECRAB comes with an already-integrated, open-source, foboot-based DFU bootloader to load new bitstreams of FPGA code or firmware with RISC-V code straight into that Flash we touched on earlier. To activate it, you just need to hold down the button while plugging in the board. Additionally, you can reprogram the Lattice FPGA directly via the JTAG or with a SPI bypass mode.
Original designer, Greg Davill, recommends utilizing Linux-for-LiteX, available on GitHub, to execute basic tasks during the customization process like defining function stubs and registers for your peripherals, compiling and embedding firmware, and documenting things like memory maps.
This ORANGECRAB was designed for versatility — its relatively generic hardware and use of a programmable processor makes that pretty clear. Emphasizing that point even more, the ORANGECRAB actually conforms to Adafruit’s Feather size specification, meaning that if you want or need to, you can hook it up to any other compliant Feather or Wing board. And while it may be small, it utilizes all six layers in its stack to make sure all signals passing through and passive RLC parts are supported.
The ORANGECRAB is a certified open source project developed in KiCad, with all its design files and examples available for access in GitHub repositories. Support for MicroPython and CircuitPython is still a work in progress, according to the product page on GroupGets, but you can currently use your board with RISC-V firmware or FPGA gateware with Verilog or other high-level languages like Chisel and the aforementioned LiteX.
If you’d like to grab your own, you can place an order from manufacturer GroupGets for $178. Of course, you can also always enter this week’s raffle below for a chance to win one for free — if you do win, we’ll even ship it right to your door. Good luck!
