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Python-based Portable IP-core Synthesis Framework for FPGA-based Computing
Verilog Python C Makefile Objective-C Tcl
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Python-based Portable IP-core Synthesis Framework for FPGA-based Computing

Copyright (C) 2013, Shinya Takamaeda-Yamazaki



Apache License 2.0 (

What's PyCoRAM?

PyCoRAM is a Python-based portable IP-core synthesis framework with CoRAM (Connected RAM) memory architecture.

PyCoRAM framework generates a portable IP-core package from computing logic descriptions in Verilog HDL and memory access pattern descriptions in Python. Designers can easily build an FPGA-based custom accelerator using a generated IP-core with any common IP-cores on vendor-provided EDA tools. PyCoRAM framework includes (1) the Verilog-to-Verilog design translation compiler and (2) the Python-to-Verilog high-level synthesis (HLS) compiler for generating control circuits of memory operations.

There are some major differences between PyCoRAM and the original soft-logic implementation of CoRAM.

  • Memory access pattern representation in Python
    • The original CoRAM uses C language to represent a memory access pattern (called 'control thread').
    • In PyCoRAM, you can easily describe them by using popular lightweight scripting language.
    • A Python script of memory access patterns is translated into an RT-level hardware design in Verilog HDL by the Python-to-Verilog high-level synthesis compiler.
  • Commercial interconnect supports (AMBA AXI4 and Altera Avalon)
    • The original CoRAM uses CONNECT to generate an on-chip interconnect.
    • PyCoRAM compiler generates a IP-core design with AMBA AXI4 or Altera Avalon. Both are commonly used on vendor-provided EDA tools.
  • Parameterized RTL Design Support
    • The original CoRAM has some limitations in Verilog HDL description of computing logic, such as no supports of generate statement.
    • PyCoRAM has a sophisticated RTL analyzer/translator to convert RTL descriptions into synthesizable IP-core package under memory abstractions of CoRAM.



  • Python (2.7 or later, 3.3 or later)
  • Icarus Verilog (0.9.6 or later)
    • 'iverilog -E' command is used for preprocessing Verilog source code.
  • Jinja2 (2.7 or later)
    • The code generator uses Jinja2 template engine.
    • 'pip install jinja2' (for Python 2.x) or 'pip3 install jinja2' (for Python 3.x)
  • Pyverilog (Python-based Verilog HDL Design Processing Toolkit)
    • Install from pip: 'pip install pyverilog' for Python2.7 or 'pip3 install pyverilog' for Python3
    • Install from github into this package: 'cd Pycoram; git clone; cd pycoram; ln -s ../Pyverilog/pyverilog'

for RTL simulation

  • Icarus Verilog
    • Icarus Verilog is an open-sourced Verilog simulator
  • Synopsys VCS (option, if you have)
    • VCS is a very fast commercial Verilog simulator

for bitstream synthesis

  • Xilinx: Vivado (2014.4 or later) and Xilinx Platform Studio (14.6 or later)
  • Altera: Qsys (14.0 or later)


If you want to use PyCoRAM as a general library, you can install on your environment by using

If Python 2.7 is used,

python install

If Python 3.x is used,

python3 install

Then you can use the pycoram command from your console (the version number depends on your environment).


Getting Started

First, please make sure TARGET in '' in 'sample' is correctly defined. If you use the installed pycoram command on your environment, please modify 'TARGET' in as below (the version number depends on your environment)


You can find the sample projects in 'sample/tests/single_memory'.

  • : Control-thread definition in Python
  • userlogic.v : User-defined Verilog code using CoRAM memory blocks

Then type 'make' and 'make run' to simulate sample system.

make build
make sim

Or type commands as below directly.

python pycoram/ sample/default.config -t userlogic -I include/ sample/tests/single_memory/ sample/tests/single_memory/userlogic.v
iverilog -I pycoram_userlogic_v1_00_a/hdl/verilog/ pycoram_userlogic_v1_00_a/test/test_pycoram_userlogic.v 

PyCoRAM compiler generates a directory for IP-core (pycoram_userlogic_v1_00_a, in this example).

'pycoram_userlogic_v1_00_a.v' includes

  • IP-core RTL design (hdl/verilog/pycoram_userlogic.v)
  • Test bench (test/test_pycoram_userlogic.v)
  • XPS setting files (pycoram_userlogic_v2_1_0.{mpd,pao,tcl})
  • IP-XACT file (component.xml)

A bit-stream can be synthesized by using Xilinx Platform Studio. Please copy the generated IP-core into 'pcores' directory of XPS project.

This software has some sample project in 'sample'. To build them, please modify 'Makefile', so that the corresponding files and parameters are selected (especially INPUT, MEMIMG and USERTEST)

PyCoRAM Command Options


python [config] [-t topmodule] [-I includepath]+ [--memimg=filename] [--usertest=filename] [file]+


  • file
    • User-logic Verilog file (.v) and control-thread definition file (.py). Automatically, .v file is recognized as a user-logic Verilog file, and .py file recongnized as a control-thread definition, respectively.
  • config
    • Configuration file which includes memory and device specification
  • -t
    • Name of user-defined top module, default is "userlogic".
  • -I
    • Include path for input Verilog HDL files.
  • --memimg
    • DRAM image file in HEX DRAM (option, if you need). The file is copied into test directory. If no file is assigned, the array is initialized with incremental values.
  • --usertest
    • User-defined test code file (option, if you need). The code is copied into testbench script.


  • Shinya Takamaeda-Yamazaki, Kenji Kise and James C. Hoe: PyCoRAM: Yet Another Implementation of CoRAM Memory Architecture for Modern FPGA-based Computing, The Third Workshop on the Intersections of Computer Architecture and Reconfigurable Logic (CARL 2013) (Co-located with MICRO-46), December 2013. Paper Slide

  • Zynq + PyCoRAM (+ Debian) (slideshare, in Japanese) Slide

  • PyCoRAM for HLS meet up (slideshare, in Japanese) Slide

Related Project


  • Python-based Hardware Design Processing Toolkit for Verilog HDL
  • Used as basic code analyser and generator in PyCoRAM


  • A General Purpose Memory Architecture for FPGAs
  • The original CoRAM developed at CMU
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