Created: 2012-03-21 21:06
Updated: 2019-03-01 12:51
License: apache-2.0


Repository for Verilog building blocks with a high chance of reuse across different hardware projects (e.g. debouncers, display drivers).

Most of these modules are well tested and shouldn't have issues. However, I'm generally allowing myself to upload things which may have issues.


  • button_debounce.v -- Timing-based button debouncing circuit.

  • pipeline_registers.v -- A parameterized number of pipeline registers of some depth and width. This is primarily useful as a building block for other modules.

  • pipeline_registers_set.v -- Pipeline registers (as above), but with the ability to set the value of the registers.

  • ram_infer.v -- Xilinx standard module that will infer RAM during FPGA synthesis.

  • reset.v -- Implements a "good" reset with asynchronous assertion and synchronous de-assertion.

  • sign_extender.v -- Explicit sign extender (this should be unnecessary in Verilog...)

  • sqrt_pipelined.v -- A pipelined implementation of a fixed point square root. Deprecated due to complexity and incorrect rounding.

  • sqrt_generic.v -- A refactor of sqrt_pipelined.v into a cleaner syntax. This uses implicit truncation rounding and will show a resulting bias towards negative infinity.

  • uart_rx.v -- UART receiver.

  • uart_tx.v -- UART transmitter.

  • div_pipelined.v -- Pipelined division module (largely untested)


In an attempt at modularity, I'm now including a submodules directory which is intended to contain other repositories (of mine most likely, but not restricted as such) that are useful. These can be pulled in with:

git submodule init
git submodule update

And recursively updated with:

git submodule foreach git pull origin master
  • hdl-tools -- Basically, a dumping ground of scripts I've written that make working with HDLs easier. For example, addWavesRecursive.tcl will populate a GTKWave configuration with the module hierarchy found in a VCD file.
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