lib

Verilog Library from Project F

The Project F Library includes handy Verilog designs for everyone. You can freely build on these MIT licensed designs. Get an overview from the Verilog Library blog or dive into the designs.

Library Areas

• clock - clock generation (PLL) and domain crossing
• display - display timings, framebuffer, DVI/HDMI output
• essential - handy modules for many designs
• graphics - drawing lines and shapes
• maths - divide, LFSR, square root...
• memory - roms and ram designs, including BRAM
• null - null modules for linting
• res - palettes, fonts, and resource files for testing
• uart - UART (serial) transmitter/receiver

NB. Documentation and test benches are still being added.

FPGA Architecture

Our designs seek to be vendor-neutral, but some functionality requires support for vendor primitives. We currently support two FPGA architectures:

• XC7 - Xilinx 7 Series FPGAs, such as Spartan-7 and Artix-7
  • BUFG, MMCME2_BASE
  • HDMI support: OBUFDS, OSERDES2
• iCE40 - Lattice iCE40 FPGAs, such as iCE40 UltraPlus
  • SB_IO, SB_PLL40_PAD, SB_SPRAM256KA

We also infer block ram (BRAM); see memory.

Porting to other architectures should be straightforward.

SystemVerilog?

We use a few simple features of SystemVerilog to make Verilog more pleasant:

• logic type is safer and less work than using wire and reg
• always_comb and always_ff to make intent clear and catch mistakes
• $clog2 to calculate vector widths (e.g. for addresses)
• enum to make finite state machines simpler to work with
• Matching names in module instances: .clk_pix instead of .clk_pix(clk_pix)

I believe these features are helpful, especially for beginners. All the SystemVerilog features are compatible with recent versions of Verilator, Yosys, Icarus Verilog, and Xilinx Vivado.

For other designs from Project F, see the main README or visit projectf.io.

Resource Licences

Resources in this repository, such as fonts and palettes, may have their own licences. In such cases, the licence is clearly stated at the top of each file. For example, GNU Unifont in lib/res/fonts/font_unifont_8x16.mem.