I wanted to share with you a board that a couple of us have been working on for the last few months. We put it together to be an easy-to-access ARM Cortex-M4F flight controller. We also got a little frustrated with the STM peripherals library, so we've been building out a c++ object peripherals library that's open source with a nice, flexible expat license. Let me know if you have any comments, questions, or suggestions!
Board info (and lots of other random stuff): http://ashimadevices.com
Here's some info on the board. In the image, above, there are two prototypes we made, top has a XBee and the programmer / power board attached. The bottom has the two boards separated and the XBee removed.
main board - 64mm x 35mm; 15g; 3.3v in (5v tolerant I/O)
programmer / power board - 27 mm x 35 mm; 7g; 6-20v in / 3.3v and 5v out
Processor: 168 MHz 32-bit Cortex-M4F (FPU); 1Mb Flash; 192K SRAM; 5v tolerant I/O; 14 timers; CRC and RNG units; 96 bit unique ID; RTC calendar; I2C, SPI, USART I/O; USB; 3 ADC, 1 DAC
IMU: MPU 9150 - board centered with colocated mag, gyro and accel; BMP180 pressure (MS5611 ready, but these parts have been hard to source)
Support components: A high-speed 4-bit SDIO micro-SD card slot for logging. 8 Kbytes of EEPROM on the board. For testing and quick board state assessment, we included 3 user and 4 status LEDs. There's also a 1W audio amp in lieu of a buzzer.
Comms: XBee module (or XBee compatible) ready
Programming: The USB interface is broken-out via the power board specifically to allow development and programming.
Control: We put a host of the usual I/O on the board. Here's a break out diagram: