* NEO430 Processor (MSP430-compatible)

Project maintainers


Name: neo430
Created: Oct 16, 2015
Updated: Dec 6, 2019
SVN Updated: Dec 6, 2019
SVN: Browse
Latest version: download (might take a bit to start...)
Statistics: View
Bugs: 3 reported / 3 solved
Star11you like it: star it!

Other project properties

Development status:Stable
Additional info:Design done, FPGA proven, Specification done
WishBone compliant: Yes
WishBone version: B.4
License: LGPL

Table of Content


Welcome to The NEO430 Processor project!

You need a small but still powerful, customizable and microcontroller-like processor system for your next FPGA project? Then the NEO430 is the right choice for you.

This processor is based on the Texas Instruments MSP430(TM) ISA and provides full compatibility with the original instruction set. The NEO430 is not an MSP430 clone – it is more like a complete new implementation from the bottom up. The processor features a very small outline, already implementing standard features like a timer, a watchdog, UART, TWI and SPI serial interfaces, general purpose IO ports, an internal bootloader and of course internal memory for program code and data. All of the implemented peripheral modules are optional – so if you do not need them, you can exclude them from synthesis to reduce the size of the system. Any additional modules, which make a more customized system, can be connected via a Wishbone-compatible bus interface or directly implemented within the processor. By this, you can built a system, that perfectly fits your needs.

It is up to you to use the NEO430 as stand-alone, configurable and extensible microcontroller, or to use it as controller within a more complex SoC design.

The high-level software development is based on the free TI msp430-gcc compiler tool chain. You can either use Windows (PowerShell or Linux Subsystem) or Linux as build environment for your applications – the project supports both worlds.

This project is intended to work "out of the box". Just synthesize the test setup from this project, upload it to your FPGA board of choice (the NEO430 uses a FPGA vendor-independent VHDL description) and start exploring the capabilities of the NEO430 processor. Application program generation works by executing a single "make" command. Jump to the "Let’s Get It Started" chapter in the NEO430 documentary, which provides a lot of guides and tutorials to make your first NEO430 setup run: NEO430 Datasheet NEO430 Datasheet

Processor Features

NEO430 Overview

(optional modules are marked using dashed lines in the figure above)

  • 16-bit open source soft-core microcontroller-like processor system
  • Full support of the original MSP430 instruction set architecture
  • Code-efficient CISC-like instruction capabilities
  • Tool chain based on free TI msp430-gcc compiler
  • Application compilation scripts (makefiles) for Windows Powershell / Windows Subsystem for Linux / native Linux
  • Software requirements (regardless of platform):
    • TI msp430-gcc compiler
    • native GCC compiler
    • GNU Make
  • Completely described in behavioral, platform-independent VHDL (no macros, primitives, attributes, etc. used)
  • Fully synchronous design, no latches, no gated clocks
  • Very low resource requirements and high operating frequency
  • Internal DMEM (RAM, for data) and IMEM (RAM or ROM, for code), configurable sizes
  • One external interrupt line
  • Customizable processor hardware configuration:
    • Optional multiplier/divider unit (MULDIV)
    • Optional high-precision timer (TIMER)
    • Optional universal asynchronous receiver and transmitter (UART)
    • Optional serial peripheral interface (SPI)
    • Optional I2C-compatible two wire serial interface (TWI) supporting clock stretching
    • Optional general purpose parallel IO port (GPIO), 16 inputs & 16 outputs, with pin-change interrupt and PWM option
    • Optional 32-bit Wishbone bus interface adapter (WB32) - including bridges to Avalon (TM) bus and AXI4-Lite (TM)
    • Optional watchdog timer (WDT)
    • Optional cyclic redundancy check unit (CRC16/32)
    • Optional custom functions unit (CFU) for user-defined processor extensions
    • Optional 4 channel PWM controller with 1 to 8 bit resolution (PWM)
    • Optional Galois Ring Oscillator (GARO) based true random number generator (TRNG)
    • Optional external interrupts controller with 8 independent channels (EXIRQ), can also be used for software-triggered interrupts (traps, breakpoints, etc.)
    • Optional internal bootloader (2kB ROM) with serial user console and automatic boot from external SPI EEPROM

Differences to the Original MSP430 Processors

  • Completely different processor modules with different functionality
  • Up to 48kB instruction memory and 12kB data memory
  • NEO430 tool chain (makefiles, boot-code and linker script) required for application compilation
  • Custom binary executable format
  • No hardware debugging interface
  • No analog components
  • No support of TI's Code Composer Studio
  • No default support of CPU's DADD instruction (but can be enabled in package)
  • Just 4 CPU interrupt channels
  • Single clock domain for complete processor
  • Different numbers of instruction execution cycles
  • Only one power-down (sleep) mode
  • Wishbone-compatible interface to attach custom IP
  • Internal bootloader with text interface (via UART serial port)
  • Extended ALU functions (if enabled)

Implementation Results

Mapping results generated for HW version 0x0320. The full (default) hardware configuration includes all optional processor modules (excluding the CFU, the TRNG and the DADD instruction), an IMEM size of 4kB and a DMEM size of 2kB. The minimal configuration only includes the CPU and the GPIO module. Results generated with Xilinx Vivado 2017.3, Intel Quartus Prime Lite 17.1 and Lattice Radiant 1.1 (Synplify)

Xilinx Artix-7 (XC7A35TICSG324-1L)LUTsFFsBRAMsDSPsf_max*
Full (default) configuration:983 (4.7%)1014 (2.5%)2.5 (5%)0 (0%)100 MHz
Minimal configuration (CPU + GPIO):685 (3.3%)290 (0.7%)1 (2%)0 (0%)100 MHz
Intel Cyclone IV (EP4CE22F17C6)LUTsFFsMemory bitsDSPsf_max
Full (default) configuration:1648 (7%)990 (4%)65800 (11%)0 (0%)122 MHz
Minimal configuration (CPU + GPIO):596 (3%)233 (1%)49408 (8%)0 (0%)126 MHz
Lattice iCE40 UltraPlus (iCE40UP5K-SG48I)LUTsFFsEBRsDSPsSRAMsf_max*
Full (default) configuration:2600 (49%)1152 (21%)16 (53%)0 (0%)0 (0%)20 MHz
Minimal configuration (CPU + GPIO):1365 (25%)493 (9%)12 (40%)0 (0%)0 (0%)20 MHz

*) Constrained

Device Utilization by Entity

The following table shows the required resources for each module of the NEO430 processor system. Note that the provided numbers only represent a coarse overview as logic elements might be merged and optimized beyond module boundaries.

Mapping results generated for HW version 0x0320. The full (default) hardware configuration includes all optional processor modules (excluding the CFU and DADD instruction but including the TRNG), an IMEM size of 4kB and a DMEM size of 2kB. Results were generated using Intel Quartus Prime Lite 17.1.

Intel Cyclone IV (EP4CE22F17C6)LUTsFFsMemory BitsDSPs
Bootloader Memory (Boot ROM, 2kB)21163840
Central Processing Unit (CPU)5061712560
Checksum Unit (CRC)1109400
Custom Functions Unit (CFU)----
Data Memory (DMEM, 2kB)61163840
IO Port Unit (GPIO)494500
Instruction Memory (IMEM, 4kB)41327680
Multiplier & Divider (MULDIV)18413100
Pulse-Width Modulation Unit (PWM)806600
Serial Peripheral Interface (SPI)574300
System Info Memory (SYSCONFIG)151300
High-Precision Timer (TIMER)705500
True Random Number Generator (TRNG)443600
Two Wire Interface (TWI)804100
Universal Asynchronous Rx/Tx (UART)1298900
Wishbone Interface (WB32)12811700
External Interrupts Controller (EXIRQ)725400
Watchdog TImer (WDT)493600

Quick Start

  • At first, get the most recent version the NEO430 Processor project from GitHub:

    • Clone the NEO430 repository using git from the command line (suggested, as this allows easy project updates via git pull):

      git clone
    • Or download the current version of this project as ZIP file:

  • Next, install the free MSP430-GCC compiler toolchain from the TI homepage (select the "compiler only" package according to your system OS):

  • Make sure GNU Make and a native GCC compiler are installed (double check for the newest versions)

  • Follow the instructions from the "Let's Get It Started" section of the NEO430 documentary: NEO430 Datasheet NEO430 Datasheet

  • This documentary will guide you to create a simple test setup, which serves as "hello word" FPGA demo:

NEO430 Test Example Setup

  • The NEO430 project also includes some example programs from which you can start your own application: SW example projects

  • Have fun! =)

Change Log

The official change log of this project can be found at the end of the NEO430 Datasheet NEO430 Datasheet.


If you have any questions, bug reports, ideas or if you are facing problems with the NEO430, feel free to drop me a line. Also, I'm always happy to hear what cool projects you are realizing with this core :smiley:


If you are using the NEO430 for some kind of publication, please cite it as follows:

S. Nolting, "The NEO430 Processor",

This is a hobby project released under the LGPL-3.0 license. No copyright infringement intended.

This project is not affiliated with or endorsed by the Open Source Initiative ( /

This source file may be used and distributed without restriction provided that this copyright statement is not removed from the file and that any derivative work contains the original copyright notice and the associated disclaimer.

This source file is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This source is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this source; if not, download it from

"MSP430" and "Code Composer Studio" are trademarks of Texas Instruments Corporation.

"Windows" is a trademark of Microsoft Corporation.

"Virtex", "Artix" and "Vivado" are trademarks of Xilinx Inc.

"Cyclone", "Quartus" and "Avalon Bus" are trademarks of Intel Corporation.

"iCE40 UltraPlus", "Lattice Radiant" and "Lattice Diamond" are trademarks of Lattice Semiconductor Corporation.

"AXI", "AXI4" and "AXI4-Lite" are trademarks of Arm Holdings plc.

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