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Name: t400
Created: May 5, 2006
Updated: Aug 19, 2009
SVN Updated: May 29, 2009

Other project properties

Category: Processor
Language: VHDL
Development status: Stable
Additional info: Design done , FPGA proven
WishBone Compliant: No
License: GPL


The T400 µController is an implementation of National's 4-bit COP400 microcontroller family architecture. It is intended to be used as a replacement for the original chip in SOCs recreating legacy systems.

Its final target is to provide design variants that are compatible with the COP420/421 and COP410L/411L family members. All of them derived from the common t400_core design. Such a sample system has been implemented in several FPGA families.

  • COP421-like features
  • 64 bytes internal RAM
  • 1024 bytes internal ROM (only small part used for program)
  • 4 MHz required performance

The implementation has been done with the free version of the vendor tools (Quartus II 7.2sp3 and ISE 10.1). Your mileage may vary.

Altera EP1C12Q240C8:

  • 583 / 12060 Logic Elements
  • 8,448 / 239,616 Memory Bits (RAM & ROM implemented in memory block)
  • 59 MHz maximum registered performance

Xilinx Spartan-IIE XC2S300EPQ208-6:

  • 643 / 6144 Logic Cells
  • 2 / 16 Block RAMs (RAM & ROM implemented in memory block)
  • 60 MHz maximum registered performance

The T400 µController has been successfully integrated in the FPGA Adventure Vision project.


The following tools are integrated and are required for this project:

  • The Macro Assembler AS
  • The GHDL simulator
  • The Perl scripting language


The project has Stable status:

  • All of the targeted functionality is implemented in synthesizable VHDL.
  • Verification suite is available containing self-checking assembler patterns for all implemented instructions.
  • All instructions implemented and verified with black-box tests.
  • Toplevel system designs resembling COP420, COP421, COP410L and COP411L are available and verified with regression test suite.
  • Proven synthesizability for different FPGA families.
  • Stable interfaces for internal modules.

Known bugs will be logged on the Tracker page . Please feel free to enter any problems you encounter with this core.


The COPS Family User's Guide and the specific datasheets can be downloaded from DatasheetArchive .


The latest release of the T400 µController project is version 1.1.

Get this and all previous versions of the design files from SVN: Download repository .

Please keep in mind that trunk/ is work in progress and might contain smaller or bigger problems.

You should also check the Tracker for known bugs and see if they affect your work.