The Making of the Wi-FIRE, Digilent’s First MZ chipKIT

A few months ago, we released a board that I heard had a pretty fantastic back story– and I went and found that it was as interesting as rumored!

Keith Vogel is one of our senior engineers at Digilent, and he loves chipKIT and is always excited to get involved with new products in the chipKIT line.
Keith Vogel is one of our senior engineers at Digilent, and he loves chipKIT and is always excited to get involved with new products in the chipKIT line. Image from chipkit.net.

In December 2013, Digilent received a cold call from Imagination Technologies.  They loved our WiFi-enabled WF32 — but what if it had the latest PIC32 MZ-architecture processor instead of the MX processor that other chipKIT products have? After all, the MZ not only show-cased Imagination’s IP core (the way the processor is put together), but it was the ideal processor to run FlowCloud, their internet of things (IoT) solution. So, they asked, “Would it be possible to have 1000 of the retooled product by March?”  It was with this seemingly out-of-the-blue call that the development of the chipKIT Wi-FIRE began!

 

Keith  began work immediately on the new Wi-FIRE , with Gene Apperson providing guidance and mentoring. A couple of hurdles came up. For starters, MZ chips didn’t exist yet in their production-ready form! Microchip was still developing the technology and you couldn’t just order one off the website. Luckily, Digilent has been working with Microchip as a third party, and through that channel, a few MZ engineering silicon samples were sent to Pullman. With the hot-off-the-line engineering silicon chips on their way to Washington, laying out the board was on everyone’s mind (everyone who knew about the project, that is). It wasn’t as simple as pulling the MX processor off the WF32 and just replacing it with the MZ processor that would arrive. The entire pin layout had to be remapped.  Some of the challenges that had to be addressed: the MZ is a peripheral pin select (PPS) processor, which means that you can assign pins flexibly. The MZ processor also has a greater number of peripherals, which allowed for a dedicated SPI port for the SD card! Additionally, the MX MCU is mostly 5V-tolerant, while the MZ is predominantly only 3.3V-tolerant.

 

There ended up being three iterations of the Wi-FIRE: the UDB board, the prototype, and the current (first!) revision of the board! These hardware iterations tell the story of the development of the board, showing many of its challenges and victories.

WiFIRE-dev-history

The Universal Development Board (UDB) was a fast way that Keith could test out and develop the software. The board allows a software developer to plug in a plug-in module (PIM) populated with the processor of choice (in our case it was the MZ) and have access to all of the peripherals and pins.

Gene developed the UDB board Microchip provided the PIM and Keith started the software development for the Wi-FIRE bootloader.
Gene developed the UDB board Microchip provided the PIM and Keith started the software development for the Wi-FIRE bootloader.

While the software was being developed, some anomalies in the silicon of the MZ surfaced that needed to be addressed. Luckily, Digilent and Microchip have a close partnership, and by working together, they were able to get to the bottom of  the issues and develop software errata for the best functionality, not only for Digilent’s Wi-FIRE board, but all MZ users. These developments and changes were shared right away (The latest version of MPIDE has those updates)!

The name was WiFi MZ--we hadn't settled on a name yet.
The name was WiFi MZ–we hadn’t settled on a name yet.

By February, there were six prototypes of the Wi-FIRE ready. However, they were some production kinks to work out.  Attempts to tune the crystals for a crystal circuit on the board weren’t as successful as hoped, so they eschewed the original design in favor of using a 24 MHz oscillator. Once this was done,  the board was functional!  Within hours, we had our network stack running on the Wi-FIRE. With the state-of-the-art MZ, Imagination got their prototypes to develop their own software on top of ours. Digilent got the go-ahead to continue development to take the board into production!

The production-ready Wi-FIRE!
The production-ready Wi-FIRE!

In March, after months of productive development time and a few hiccups in development–a couple of hand-soldered chips (MZ parts still were not released)–the Wi-FIRE (with pre-released A4 engineering silicon) was officially ready for release! It was announced at Imagination Tech’s summit, and they gave away 500 Wi-FIRE boards to their developers! At the same time, Digilent made it available to the public and it’s for sale on our website now.

box-WiFIRE

The board has received  a lot of positive attention, and it’s been showcased to great fanfare. Imagination has successfully used their JTAG debugger and is fully compatible with MPIDE and MPLAB X. While created with Imagination’s FlowCloud in mind, there are a lot of exciting projects that can be done with the chipKIT Wi-FIRE. The production release is on the horizon when we replace the engineering silicon with Microchip’s production silicon to have the most advanced PIC32 WiFi-enabled development platform on the market.

chipKIT-WiFIRE

I know that all of us at Digilent are excited to see such a fun product. Make sure you go and check out the board on the Digilent website and/or the chipKIT.net webpage!

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About Amber Mear

I was the Digilent blog editor, and now I'm a contributor. I love learning about wearables and writing about social issues in STEM. Outside of work, I can be found watching Netflix with my cat, working on an art project, or trying to find new, delicious local foods.

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