Give Your RPi A Cool FPGA Hat

November 5, 2016 by Eric Evenchick 32 Comments

Need additional, custom IO for your Raspberry Pi? Adding an FPGA is a logical way to expand your IO, and allow for high speed digital interfaces. [Eric Brombaugh]’s Icehat adds a Lattice iCE5LP4K-SG48 FPGA in a package that fits neatly on top of the Raspberry Pi Zero. It also provides a few LEDs and Digilent compatible PMOD connectors for adding peripherals. The FPGA costs about six bucks, so this is one cheap FPGA board.

The FPGA has one time programmable memory, but can also be programmed over SPI. This allows the host Pi to flash the FGPA with the latest bitstream at boot. Sadly, this particular device is not supported by the open source Icestorm toolchain. Instead, you’ll need Lattice’s iCEcube2 design software. Fortunately, this chip is supported by the free license.

Icehat is an open source hardware design, but also includes a software application for flashing a bitstream to the FPGA from the Pi and an example application to get you started. All the relevant sources can be found on Github, and the PCB is available on OSHPark.

While this isn’t the first pairing of a Raspberry Pi and FPGA we’ve seen, it is quite possibly the smallest, and can be built by hand at a low cost.

Introducing Hat A Day! Not To Be Confused With The Real HaD Of Course…

August 22, 2014 by James Hobson 18 Comments

Hat a Day

With the release of the Raspberry Pi B+ model comes a whole slew of extra GPIO connectors, a whopping 40 of them in fact — Almost double the original B model! A HAT stands for Hardware Attached on Top, and Adafruit is celebrating by trying to create a new hat, every day.

A HAT is a rectangular board measuring 65x56mm with mounting holes for the Raspberry Pi B+ and a 40 pin GPIO header. That doesn’t sound too special by itself, but two of the header pins are reserved for a special auto-configuration system that allows your Pi to have automatic GPIO and driver setup! Now we’re talking!

So far Adafruit has made a handful of prototype HATs including the Perma-proto HAT, a GPS HAT, a TFT HAT, an Arcade HAT and even a Servo HAT. But they’re looking for more! We think they’ve slipped up on the one a day record though…

We’re excited to see more integrated projects with the B+ since it’s so much more friendly for add-on hardware than the original — What kind of hardware would you like to see in HAT form? Do you like the idea of HATs?