sifferman / tangnano_example

Simple example of how to get started with the Tang Nano with FuseSoC.

Tang Nano Example

Repository: https://github.com/E4tHam/tangnano_example

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About

The Tang Nano is the famous / infamous $5 FPGA (learn more here). This repository is a simple example of how to get started with the Tang Nano with FuseSoC.

The RTL implements an adder.

Usage

make tangnano   # generate the bitstream
make load       # load the bitstream to the Tang Nano SRAM

make lint       # verify code meets Verilator standards
make sim        # simulate in icarus
make view       # open dump in gtkwave

make clean      # remove build files

Requirements

• FuseSoC
• Icarus Verilog
• GTKWave
• Verilator
• Apicula
• yosys
• nextpnr-gowin
• openFPGALoader

Programming Flash

As of (2/22/22) programming the flash has difficulties. This is a collection of problems I encountered and their solutions. Hopefully in the future these will be resolved. :)

• Currently, openFPGALoader does not support writing to internal flash via the USB port. An external JTAG probe is required. trabucayre/openFPGALoader#32 To write to the flash, you must use Gowin's proprietary programmer.
• There is a bug in the official release of Gowin's FPGA programmer. You will need this version or higher: Gowin Programmer 2.
• By default, Gowin's programmer has a programming frequency set to 30MHz, but the Tang Nano only supports up to 25MHz. Change the cable settings and set it lower; 2.5MHz is common.