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FPGA-Devboard with iCE40

Former Member
Former Member

Hey everyone!

 

I recently decided to teach myself VHDL and pretty quickly settled with the Idea of designing my own dev-board with an iCE40HX4K.

I used one from Lattice because at work they are preferred (for whatever reason). I wanted to include a lot of peripherals on the board itself so I don't have to use breadboards constantly and this is what finally came out of it:

 

image

The board has:

  • 8 LEDs
  • 8 button Inputs
  • a 10-pin header with Z-Diode protection (later Use as Logic Analyzer intended)
  • VGA-connector
  • 3 7-Segment displays
  • I2C peripherals (LM75 temp sensor, 8 channel 10bit ADC with TMP36 analog temp sensor on channel 0)
  • a PMOD Port for future Modules
  • 18 IOs on a pin header

 

External SPI-Flash programming and UART interface via FT2232H, USB acting as power supply with integrated 3.3V and 1.2V voltage regulators.

 

So far so good, currently I'm learning the basics in VHDL. Already I can do more things than expected, but I'm far from fluent image

Finished Milestones:

  • "Hello World" (button activates LED)
  • Button debouncing
  • 7-segment decoding
  • counters and registers
  • processes, functions, packages, records and components

 

Milestones ahead:

  • UART communication
  • SPI communication
  • I2C communication
  • VGA output
  • Logic Analyzer with VGA display (Memory using internal 80kb BRAM as proof of concept)

 

Do you have any ideas what else I could do? Any idea would help me practicing and improving, so I'm thankful for every suggestion image

 

Best regards

  • Nice board!

     

    iCE40 is a nice FPGA architecture.  It's clean and simple -- I would consider it the best choice for someone starting out.  A terrific feature is that iCE40 has open source "Free as in Freedom" tools so you're not handcuffed to vendor tools.

  • Well done for getting your own board off the ground !

     

    Your milestones look like a pretty good start.

     

    You could consider adding a Microchip serial RAM using some of you spare IO pins - that would make your logic analyser a bit more capable.

    They do 1Mbit versions of the pure ram but also the amazing instant back up non volatile version.

     

    MK

  • Former Member
    Former Member in reply to johnbeetem

    thanks!

     

    Well, the iCE40s are not simple and clean, but also cheaper than Xilinx FPGAs (which are way too big for beginning). Sure, you can do much more on the Xilinx series, but I just wanted to learn VHDL image

     

    And regarding to the open Source toolchains: this seems only to apply to Verilog with Yosys and the related tools, for VHDL there is GHDL, but it seems it doesn't support a lot of features. For now I'm using the Lattice tools, when I try to synthesize my designs with GHDL it throws errors on me for some reason... I think I have to look further into it, but for now I just try to focus on learning how to code in VHDL image

  • Former Member
    Former Member in reply to michaelkellett

    Thanks for oyur input!

     

    I already considered adding a RAM chip to the board for this exact reason, but ended up not doing so for various reasons.

    Since this is just a development board, I use it to play around, getting familiar with the architecture and VHDL and just test things.

    When I'm confident enough to create a more functioning logic analyzer, I will create another board with less peripherals and a bigger parallel chip (so I dont have to use multiple chips, one for each channel). See this board as a Trial and Error. Also I still have to make a Program which is controlling, triggering and setting up the FPGA. Including configuring the PLL and sample depth.

    With this board, learning multiple different concepts works great and it was never intended to do much more. Maybe when I'm done with these boards I can make something useful with them, but not now ^^