Maple is an open-source development environment for ARM Cortex based microcontrollers. Maple boards come in an Arduino-compatible format, complete with Arduino pin layouts and programming environment. The Arduino compatible form-factor allows you to use the various available Arduino Shields (add-on boards) with Maple processor boards.
This Maple board uses an STM32F103RBT6 microcontroller (ARM Cortex-M3 core) instead of an 8-bit AVR, thus offering much higher computing speed.
The Olimexino-STM32 takes Maple a step further, addressing issues brought up by Arduino and Maple users, implementing features that have been on Arduino users' wish lists for years:
The pictures on this page are of board Revision A. The board currently shipping is Revision D. All the interfaces and connectors are in the same locations, however (Revision C of the board had replaced the power jack with screw terminals, but Revision D returns the original power jack as shown here).