This version of marlin is modified to make serial connection (print over OctoPrint as an example) more stable without resends, checksum errors, buffer overflows or other issues present in other custom firmware. For complicated G-code I included Arc. To enable this in Cura go to Marketplace, search Arc Welder, restart Cura and select your model and check the Arc Weld on the right sides settings. Other slicers have other means to enable arcs.

IMPORTANT — Hardware compatibility

This firmware targets the Ender 3 V3 SE with the Creality C14 motherboard (for example: CR4NS200320C14). Do NOT flash this firmware on C13 or other board revisions — flashing the wrong hardware revision can brick the board. See How to check whether your board is C13 or C14 for details.

PlatformIO Inspection

RAM: [== ] 23.5% (used 15416 bytes from 65536 bytes)

Flash: [==== ] 41.9% (used 215416 bytes from 514288 bytes)

Table of Contents

• Overview
• Version
• Installation
• Included Binary
• Memory Usage
• Compatibility
• Building
• Features
• Contributing
• Support
• License

Overview

This repository contains a customized Marlin 2.1.2 firmware build tuned for the Creality Ender‑3 V3 SE (C14 motherboard). The project focuses on a modular, testable configuration that stays within the memory limits of the stock C14 board while providing commonly requested UX and motion features.

Version

• Firmware base: Marlin bugfix-2.1.x (navaismo https://github.com/navaismo/Marlin_bugfix_2.1_E3V3SE)
• Project release: 2.1.2 (this repository)
• Maintainer: Revoxxi (custom modifications and configuration)

Installation

1. Verify your board is a Creality C14. Do NOT flash this firmware on C13 or other revisions; doing so can brick the board. See docs/C14_check.md for identification steps.
2. Use the prebuilt binary in .pio/build/STM32F401RE_creality/firmware.bin or build your own (instructions below).
3. Follow the flashing instructions in docs/Flashing.md or the project's wiki pages. Always keep a working backup of your original firmware and configuration.

Included Binary

The distributed binary is a conservative feature set chosen to balance functionality and memory usage. It includes:

• DWIN thumbnail rendering
• D routine auto Z offset
• Input shaping (optional via UI)
• Linear Advance
• LCD dim/brightness menu and extra UI tweaks
• CRTouch helpers and test functions

If you need a different feature set, build a custom binary from the provided Marlin configuration files.

Memory Usage

Measured from a representative build (PlatformIO environment STM32F401RE_creality):

RAM:   15,416 bytes (23.5% of 65536 bytes)
Flash: 215,448 bytes (41.9% of ~514288 bytes)

These values are from a local build and may change when enabling/disabling features. Use PlatformIO Home → Project Inspect or platformio run -t size to re-check memory usage after changes.

Compatibility

This firmware targets the Ender‑3 V3 SE with the Creality C14 motherboard (for example: CR4NS200320C14). Do NOT flash on C13 or other revisions — check docs/C14_check.md before proceeding.

Building

Recommended: Visual Studio Code with the PlatformIO extension.

To build from the repository root with the included virtual environment:

# From repo root
.venv\Scripts\python.exe -m platformio run -e STM32F401RE_creality

To inspect sizes:

.venv\Scripts\python.exe -m platformio run -e STM32F401RE_creality -t size

To build a custom configuration, edit Marlin/Configuration.h and Marlin/Configuration_adv.h then rebuild.

Features

The project includes a number of user-facing and motion-related features; highlights:

• Input Shaping (configurable per-axis)
• FT_MOTION / FTM_SMOOTHING for trajectory smoothing
• Linear Advance
• DWIN UI additions: thumbnail, dim/brightness, custom extrude, preheat labels
• CRTouch utilities and enhanced Z offset routines

If you want to further reduce memory/serial pressure, consider disabling Input Shaping, reducing FTM_BUFFER_SIZE, or lowering TX_BUFFER_SIZE/BLOCK_BUFFER_SIZE in Marlin/Configuration_adv.h.

Contributing

Contributions are welcome. Please open pull requests against the bugfix-2.1.x branch and include unit or build tests where applicable. See project contribution notes and use make tests-config-single-local or PlatformIO test targets to validate changes.

Support

For documentation and community help, see the Marlin docs and community channels. For project-specific questions, open an issue in this repository describing firmware version 2.1.2, platform STM32F401RE_creality, and the exact behavior observed.

License

The project follows Marlin's GPL licensing. The ## License section below contains the full GPL statement.

---

/**

• Advanced configuration */ #define FTM_BUFFER_SIZE 128 // Window size for trajectory generation, must be a power of 2 (e.g 64, 128, 256, ...) // The total buffered time in seconds is (FTM_BUFFER_SIZE/FTM_FS) #define FTM_FS 1000 // (Hz) Frequency for trajectory generation. #define FTM_STEPPER_FS 2'000'000 // (Hz) Time resolution of stepper I/O update. Shouldn't affect CPU much (slower board testing needed) #define FTM_MIN_SHAPE_FREQ 20 // (Hz) Minimum shaping frequency, lower consumes more RAM

#endif // FT_MOTION

> [!TIP]
> 
> Check the [Octoprint Pinput-Shaping plugin](https://github.com/revoxxi/Octoprint-Pinput_Shaping) to get the frequencies.
>
> Check the [comparison between Marlin & Klipper Input Shaping](https://github.com/revoxxi/Octoprint-Pinput_Shaping/discussions/27).
>

<br>

### * **AXIS TWIST COMPENSATION** 
```c++
 // Add calibration in the Probe Offsets menu to compensate for X-axis twist.
    #define X_AXIS_TWIST_COMPENSATION
    #if ENABLED(X_AXIS_TWIST_COMPENSATION)
      /**
       * Enable to init the Probe Z-Offset when starting the Wizard.
       * Use a height slightly above the estimated nozzle-to-probe Z offset.
       * For example, with an offset of -5, consider a starting height of -4.
       */
      #define XATC_START_Z 0.0
      #define XATC_MAX_POINTS 3             // Number of points to probe in the wizard
      #define XATC_Y_POSITION Y_CENTER      // (mm) Y position to probe
      #define XATC_Z_OFFSETS { 0, 0, 0 }    // Z offsets for X axis sample points
    #endif

* Marlin 2.1.2 is also compatible with the CacomixtlePad for Android

And so on...

---

Marlin 3D Printer Firmware

🌍 Translations

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English	Español	Euskara	Suomi	Français	Galego	Hrvatski
Magyar	Italiano	にほんご	한국어	Nederlands	Polski	Português
Português (Brasil)	Română	Русский	Slovenčina	Svenska	Türkçe	Українська
Tiếng Việt	简体中文	繁體中文

Official documentation can be found at the Marlin Home Page.

Please test this firmware and let us know if it misbehaves in any way. Volunteers are standing by!

---

Marlin 2.1 Bugfix Branch

Not for production use. Use with caution!

Marlin 2.1 supports both 32-bit ARM and 8-bit AVR boards while adding support for up to 9 coordinated axes and to up to 8 extruders.

This branch is for patches to the latest 2.1.2 release version. Periodically this branch will form the basis for the next minor 2.1.2 release.

Download earlier versions of Marlin on the Releases page.

Example Configurations

Before you can build Marlin for your machine you'll need a configuration for your specific hardware. Upon request, your vendor will be happy to provide you with the complete source code and configurations for your machine, but you'll need to get updated configuration files if you want to install a newer version of Marlin. Fortunately, Marlin users have contributed hundreds of tested configurations to get you started. Visit the MarlinFirmware/Configurations repository to find the right configuration for your hardware. Make sure to select a compatible branch! The Marlin Download Page matches compatible software and configuration packages.

Building Marlin 2.1

To build and upload Marlin you will use one of these tools:

• The free Visual Studio Code using the Auto Build Marlin extension.
• Marlin is optimized to build with the PlatformIO IDE extension for Visual Studio Code.
• You can also use VSCode with devcontainer : See Installing Marlin (VSCode devcontainer).
• You can still build Marlin with Arduino IDE : See Building Marlin with Arduino. We hope to improve the Arduino build experience, but at this time, PlatformIO is the preferred choice.

32-bit ARM boards

Marlin is compatible with a plethora of 32-bit ARM boards, which offer ample computational power and memory and allows Marlin to deliver state-of-the-art performance and features we like to see in modern 3d printers. Some of the newer features in Marlin will require use of a 32-bit ARM board.

8-Bit AVR Boards

Marlin originates from the era of Arduino based 8-bit boards, and we aim to support 8-bit AVR boards in perpetuity. Both 32-bit and 8-bit boards are covered by a single code base that can apply to all machines. Our goal is to support casual hobbyists, tinkerers, and owners of older machines and boards, striving to allow them to benefit from the community's innovations just as much as those with fancier machines and newer baords. In addition, these venerable AVR-based machines are often the best for testing and feedback!

Hardware Abstraction Layer (HAL)

Marlin's Hardware Abstraction Layer provides a common API for all the platforms it targets. This allows Marlin code to address the details of motion and user interface tasks at the lowest and highest levels with no system overhead, tying all events directly to the hardware clock.

Every new HAL opens up a world of hardware. Marlin currently has HALs for more than a dozen platforms. While AVR and STM32 are the most well known and popular ones, others like ESP32 and LPC1768 support a variety of less common boards. At this time, an HAL for RP2040 is available in beta; we would like to add one for the Duet3D family of boards. A HAL that wraps an RTOS is an interesting concept that could be explored.

Did you know that Marlin includes a Simulator that can run on Windows, macOS, and Linux? Join the Discord to help move these sub-projects forward!

Supported Platforms

Platform	MCU	Example Boards
Arduino AVR	ATmega	RAMPS, Melzi, RAMBo
Teensy++ 2.0	AT90USB1286	Printrboard
Arduino Due	SAM3X8E	RAMPS-FD, RADDS, RAMPS4DUE
ESP32	ESP32	FYSETC E4, E4d@BOX, MRR
GD32	GD32 ARM Cortex-M4	Creality MFL GD32 V4.2.2
HC32	HC32	Ender-2 Pro, Voxelab Aquila
LPC1768	ARM® Cortex-M3	MKS SBASE, Re-ARM, Selena Compact
LPC1769	ARM® Cortex-M3	Smoothieboard, Azteeg X5 mini, TH3D EZBoard
Pico RP2040	Dual Cortex M0+	BigTreeTech SKR Pico
STM32F103	ARM® Cortex-M3	Malyan M200, GTM32 Pro, MKS Robin, BTT SKR Mini
STM32F401	ARM® Cortex-M4	ARMED, Rumba32, SKR Pro, Lerdge, FYSETC S6, Artillery Ruby
STM32F7x6	ARM® Cortex-M7	The Borg, RemRam V1
STM32G0B1RET6	ARM® Cortex-M0+	BigTreeTech SKR mini E3 V3.0
STM32H743xIT6	ARM® Cortex-M7	BigTreeTech SKR V3.0, SKR EZ V3.0, SKR SE BX V2.0/V3.0
SAMD21P20A	ARM® Cortex-M0+	Adafruit Grand Central M4
SAMD51P20A	ARM® Cortex-M4	Adafruit Grand Central M4
Teensy 3.2/3.1	MK20DX256VLH7 ARM® Cortex-M4
Teensy 3.5	MK64FX512-VMD12 ARM® Cortex-M4
Teensy 3.6	MK66FX1MB-VMD18 ARM® Cortex-M4
Teensy 4.0	MIMXRT1062-DVL6B ARM® Cortex-M7
Teensy 4.1	MIMXRT1062-DVJ6B ARM® Cortex-M7
Linux Native	x86 / ARM / RISC-V	Raspberry Pi GPIO
Simulator	Windows, macOS, Linux	Desktop OS
All supported boards	All platforms	All boards

Marlin Support

The Issue Queue is reserved for Bug Reports and Feature Requests. Please use the following resources for help with configuration and troubleshooting:

• Marlin Documentation - Official Marlin documentation
• Marlin Discord - Discuss issues with Marlin users and developers
• Facebook Group "Marlin Firmware"
• RepRap.org Marlin Forum
• Facebook Group "Marlin Firmware for 3D Printers"
• Marlin Configuration on YouTube

Contributing Patches

You can contribute patches by submitting a Pull Request to the (bugfix-2.1.2) branch.

• We use branches named with a "bugfix" or "dev" prefix to fix bugs and integrate new features.
• Follow the Coding Standards to gain points with the maintainers.
• Please submit Feature Requests and Bug Reports to the Issue Queue. See above for user support.
• Whenever you add new features, be sure to add one or more build tests to buildroot/tests. Any tests added to a PR will be run within that PR on GitHub servers as soon as they are pushed. To minimize iteration be sure to run your new tests locally, if possible.
  • Local build tests:
    • All: make tests-config-all-local
    • Single: make tests-config-single-local TEST_TARGET=...
  • Local build tests in Docker:
    • All: make tests-config-all-local-docker
    • Single: make tests-config-all-local-docker TEST_TARGET=...
  • To run all unit test suites:
    • Using PIO: platformio run -t test-marlin
    • Using Make: make unit-test-all-local
    • Using Docker + make: maker unit-test-all-local-docker
  • To run a single unit test suite:
    • Using PIO: platformio run -t marlin_<test-suite-name>
    • Using make: make unit-test-single-local TEST_TARGET=<test-suite-name>
    • Using Docker + make: maker unit-test-single-local-docker TEST_TARGET=<test-suite-name>
• If your feature can be unit tested, add one or more unit tests. For more information see our documentation on Unit Tests.

Contributors

Marlin is constantly improving thanks to a huge number of contributors from all over the world bringing their specialties and talents. Huge thanks are due to all the contributors who regularly patch up bugs, help direct traffic, and basically keep Marlin from falling apart. Marlin's continued existence would not be possible without them.

Marlin Firmware original logo design by Ahmet Cem TURAN @ahmetcemturan.

Project Leadership

Name	Role	Link	Donate
🇺🇸 Scott Lahteine	Project Lead	[@thinkyhead]	💸 Donate
🇺🇸 Roxanne Neufeld	Admin	[@Roxy-3D]
🇺🇸 Keith Bennett	Admin	[@thisiskeithb]	💸 Donate
🇺🇸 Jason Smith	Admin	[@sjasonsmith]
🇧🇷 Victor Oliveira	Admin	[@rhapsodyv]
🇬🇧 Chris Pepper	Admin	[@p3p]
🇳🇿 Peter Ellens	Admin	[@ellensp]	💸 Donate
🇺🇸 Bob Kuhn	Admin	[@Bob-the-Kuhn]
🇳🇱 Erik van der Zalm	Founder	[@ErikZalm]

Star History

License

Marlin is published under the GPL license because we believe in open development. The GPL comes with both rights and obligations. Whether you use Marlin firmware as the driver for your open or closed-source product, you must keep Marlin open, and you must provide your compatible Marlin source code to end users upon request. The most straightforward way to comply with the Marlin license is to make a fork of Marlin on Github, perform your modifications, and direct users to your modified fork.