Devices


Maple  Arduino-style STM32 Microcontroller Board Production


The Maple was LeafLab's first product, released in 2009. It was one of the first ARM Cortex-M3 microcontroller boards that was accessible to hobbyists and engineers outside of the embedded industry. The design was modeled on the Arduino boards, with a pin-out backwards compatible with most shields and a programming environment based on the free software GCC toolchain and the Processing/Wiring/Arduino user interface. LeafLabs wrote a new open source C library (libmaple) for this board, having found the vendor supplied libraries inadequate.

In 2011 a small number of "RET6 Edition" variant boards were produced, which featured a newer STM32 microcontroller with enough RAM and non-volatile flash memory to support lightweight interpreted language runtimes (eg, eLua) and real-time operating systems. This variant is no longer in production.

A longer blurb is available here. As of 2014, the Maple board is still available from distributors, but no future hardware revisions are planned and the IDE will not be ported to newer operating systems.


maple gerber


  • Dual I2C and SPI ports
  • 3 USART Serial ports
  • 7-channel DMA
  • Low power and sleep modes
  • Integrated LiPo Battery Charging
  • Dimensions: 2.05" x 2.1"
  • Extensive documentation
  • Design files under CC-BY-SA
  • STM32F103RB: a 32-bit ARM Cortex-M3 microprocessor at 72Mhz
  • 20KB RAM and 128KB Flash
  • Dedicated USB port for programming and communications
  • 43 General Purpose pins
  • 15 Analog inputs at 12-bit resolution
  • 15 PWM pins at 16-bit resolution



Maple Mini  Breadboard-able STM32 Microcontroller Board Production


Introduced in early 2011, the Maple Mini is a "breadboard-able" PCB for applications where space is limited, or simply if a breadboard is the preferred prototyping tool. Smaller than a stick of gum, Maple Mini features a smaller, 48-pin STM32 with the same speed and memory as the Maple. Maple Mini also has a complete silkscreen, making it uniquely detailed for a board its size.

As of 2014, the Maple board is still available from distributors, and we continue to integrate the off-the-shelf boards in new projects, but no future hardware revisions are planned and the IDE will not be ported to newer operating systems.

maple mini gerber

  • STM32F103RCBT6: a 32-bit ARM Cortex-M3 microprocessor at 72Mhz
  • 20KB RAM and 128KB Flash
  • Dedicated USB port for programming and communications
  • 34 General Purpose pins
  • 9 Analog inputs at 12-bit resolution
  • 12 PWM pins at 16-bit resolution



Maple Native  Deluxe STM32 Microcontroller Board Canceled


The Maple Native featured hardware similar to the Maple's, but was designed to fully exploit the powerful STM32F103 line. With twice as many pins, an additional megabyte of on-board RAM, and support for true analog output, the Maple Native design can easily handle extremely demanding tasks.

A beta run of Maple Native boards was sold in Fall 2011, and support was added to libmaple and the Maple IDE. Many design lessons were learned, and following the release of even more powerful STM32 chips, work on the Maple Native stopped and LeafLabs began designing a new "Maple II" board from scratch.

Design files and documentation for the Maple Native Beta boards are, of course, still available.

maple native


  • 2x I2C, 3x SPI ports
  • 5 U(S)ART Serial ports
  • 12-channel DMA
  • High-density FSMC Pinout
  • Low power and sleep modes
  • Integrated LiPo Battery Charging
  • Dimensions: 4" x 2.1"
  • Extensive documentation
  • Design files under CC-BY-SA
  • STM32F103ZET6: a 32-bit ARM Cortex-M3 microprocessor at 72Mhz
  • 64KB + 1MB RAM and 512KB Flash
  • Dedicated USB port for programming and communications
  • 106 General Purpose pins
  • 21 Analog inputs at 12-bit resolution
  • 2 DAC outputs at 12-bit resolution
  • 17 PWM pins at 16-bit resolution



Other Past Projects Canceled


A ground-up redesign of the Maple product line began in 2011, starting with the Maple II. The Maple II was move to the Cortex-M4 series of STM32 microcontrollers (STM32F407ZE), which feature floating-point acceleration as well as additional peripherals and significant RAM and flash memory increases. We left behind the Arduino shield pin headers and added a medium-density connector for expansion, switched to a secondary Black Magic Probe style port for programming and debugging (using a secondary WizNet microcontroller), and began work on fresh IDE using the Wiring 1.0 codebase. The Maple II hardware was prototyped (design files available), but we found it economically unfeasible to undertake another large productization and manufacturing effort. For those looking for contemporary (circa late 2013) ARM microcontroller development platforms, the Armstrap, Teensie 3.0 (most mature), and MCHCK projects are compelling, and of course STmicro, TI, and Freescale sell very low-cost development boards for Cortex-M4F microcontrollers. The Oak product line planned to combine microcontrollers with low-end FPGAs. An STM32 Cortex-M3 would be attached to a 250k gate Xilinx Spartan 3E. Oak would be a full featured processing platform suitable for robotics, machine vision, surveillance, gaming, and a host of other applications. For users who are unfamiliar with programming FPGAs, LeafLabs would offer a library of pre-compiled FPGA cores (with C interface libraries) to implement common tasks which could be achieved with the microcontroller on it's own. A hardware design was prototyped in 2012 and had basic functionality, but no integrated development environment was implemented. Cypress Semiconductor now sells a "programmable SoC" line of chips which those interested in this sort of device might want to look at. Willow was intented to be a high-performance ARM microprocessor plus FPGA board with applications in real-time machine vision, algorithm acceleration, and robotic motion control. Early research with the NVidia Tegra line of processors was promising, but the industry has moved forward significantly in recent years (eg, see the Xilinx Zynq and comparable Altera chipsets) and it is unlikely this project will be pursued. The Parallella project builds a compelling board for folks interested in this field.


Future Devices In Development


LeafLabs continues to work extensively in the open hardware digital electronics space, particularly leveraging FPGA programmable logic. We intend to release several projects in 2014, and may yet return to sling the occasional atom in addition to plain old bits and bytes.



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