What's Stopping You Building Your Next Project with an FPGA? (Please, Don't Blame the Cost!)

Greetings,

While FPGAs can be big and frighting, there cousin devices, CPLDs are more often an easier and friendlier fit to people working on embedded projects.  I have designed a lot of products where the majority of the work is being done on the microcontroller and a small amount of work is done with a CPLD.  Some examples of these designs are high speed sampling systems and high speed (non-standard) communications, where the data is in small bursts.  In these instances the CPLD can take measurements and/or collect data, while the microcontroller is doing its normal processing.  An interrupt or polling can be used to determine when data is ready. The microcontroller and CPLD can be configured to exchange data using simple I2C, serial or parallel buses.

Typically I find FPGA parts packaged in very high pin count packages with huge gate counts, while CPLDs come in smaller pin count packages with a much smaller gate count.

Gene

The Xilinx XC9572XL is the go-to device for the hobbyist. Powerful enough to solve real problems (for which conventional logic gets too large) and fast enough at the same time (faster than most MCUs). It can handle 5V on its inputs, so its compatible to many peripherals. Its quite cheap and there are many breakout boards available. Xilinx ISE is free, and programmers are cheap.

hlipka  wrote:

 

The Xilinx XC9572XL is the go-to device for the hobbyist. Powerful enough to solve real problems (for which conventional logic gets too large) and fast enough at the same time (faster than most MCUs). It can handle 5V on its inputs, so its compatible to many peripherals. Its quite cheap and there are many breakout boards available. Xilinx ISE is free, and programmers are cheap.

I used lots of XC9572XL CPLDs and the smaller XC9536XL in designs around the turn of the century.  It was a great part, and one of the last still available in a hobbyist-friendly 44-pin PLCC.  I even used wire-wrap sockets for one project

Nowadays I'd go with Lattice iCE40.  They're small, cheap FPGAs with open-source design tools available.  Not instant-on like the XC9572XL, but pretty fast load time since they're so small.  Small parts program in less than 15 msec according my quick scan of the data sheet.  You can load then from an external serial flash or use the one-time-programmable internal memory for production.

John,

I tried the Lattice tools for ICE40 devices. but I just could not get the tools to work as well as the Xilinx tools.  I liked the parts but hated the tools.  Have you had any success with them?

Gene

genebren  wrote:

 

I tried the Lattice tools for ICE40 devices. but I just could not get the tools to work as well as the Xilinx tools.  I liked the parts but hated the tools.  Have you had any success with them?

I've never used the Lattice tools for iCE40.  I've only used the open-source IceStorm tools on Ubuntu or Lubuntu GNU/Linux.

Project IceStorm: fully open-source FPGA tools for Lattice iCE40

John Beetem's IceStorm Notes

John Beetem's Arachne-pnr Notes

I haven't used IceStorm's Verilog synthesizer Yosys much.  I mostly use my XXICC (21st Century Co-design) release 0.0r , which generates iCE40 BLIF files for arachne-pnr, IceStorm's place-and-route tool.

OpenTechLabs has a nive two-part intro video, also showing installation of the open-source toolchain: https://www.youtube.com/watch?v=-bIeiMmqaZE

OpenTechLabs has a nive two-part intro video, also showing installation of the open-source toolchain: https://www.youtube.com/watch?v=-bIeiMmqaZE