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SparkFun will be closed May 25, 2015 for Memorial Day. Orders placed after 2pm on Friday the 22nd will ship out on Tuesday. Thanks!

heckler95

Member Since: November 30, 2010

Country: United States

  • I studied Operations Research and some CS and my first few years in industry were as a programmer. I got interested in electronics as a hobby about 2 years ago and developed some decent microcontroller skills, largely thanks to SparkFun. A few months back, I decided that I wanted to see what all the FPGA buzz was about and I was lucky enough to get in on the ground floor with the Mojo as a kickstarter supporter.

    I won’t say that it was easy - the shift in thinking from writing traditional code to designing ciruits in Verilog was headache-inducing at first, but the tutorials and example code on the EmbeddedMicro site really helped to illuminate things for me. My first project was a simple scrolling display on an 8x8 LED matrix. I’m not sure whether I did it “right”, but it works. The 50 Mhz clock speed of the Mojo leaves plenty of cycles for PWM, scanning rows, and scrolling the text very smoothly and evenly. I implemented a simple RAM block to hold the characters and a second block to hold the message. My next step is to wire up a serial connection via the on-board microcontroller to display any message input on the serial port.

    The Mojo takes a lot of the annoying logistics out of the way so that you can jump right in and start using the FPGA. The tutorials walk you through getting the free ISE WebPack design software from Xilinx, and EmbeddedMicro provides a Loader program that uploads your finished .bin file to the microcontroller which “programs” the FPGA, all seamlessly. I had Hello World (i.e. an LED tied to a button) up and running within minutes of getting the software stack installed. I highly recommend the Mojo as a first step toward understanding and using FPGAs.

  • The 100nF capacitor in series with DTR worked for me too. No need for pull-ups on TX/RX. Thank You!!

  • Can anybody explain why it’s safe to drive the LEDs directly from the Arduino 5v power without current-limiting resistors? I’m new to this stuff and just curious. Thanks.