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Introduction

About my first experience with FPGAs

I discovered my passion for fast programable logic during my PhD in (quantum) physics. Very helpful in these regards was the Arduino IDE, which makes microcontrollers accessible to the profane folks, i.e. makers, enthusiasts and scientists without a degree in electrical engineering. The situation is different for FPGAs, where learning VHDL/Verilog, understanding how to write synthesizable code, using the huge Xilinx/Intel toolchain, understanding the chipset architecture... involve a steep initial learning curve and a significant amount of frustration. But once these hurdles are overcome, you become capable of writing your own signal generation/acquisition systems and you are able to replace many of your old OP-27 circuits with an FPGA running a few lines of code. I had no prior experience in FPGA programming and to reach this point took me around 6 months.

About these notes

These notes intend to speed up the initial learning curve by providing working examples that incrementally incorporate new FPGA programming concepts. The hardware and software platform I use for this are:

• Redpitaya STEMlab 125-14: development board around the Xilinx Zynq-7010 SoC, which combines an ARM processor and a FPGA. The board includes digital IOs and 14-bit ADCs/DACs that operate at 125MSa/s.

• Xilinx Vivado Webpack: free version of this very complete FPGA design tool.

• PYNQ: Python environment to control FPGA designs and stream data into/out of them. It is based on Jupyter Notebooks that are executed on the ARM processor of the Zynq-7010 SoC.

Outline

• Setting up your system
• LED blink
• Analogue echo