I spent a few lunch hours poking at BradWii. Usually the ARM fork of BradWii is built in Keil, but TheLastMutt had added project files for Eclipse and GCC. I don't care for Eclipse, but for a small project I'd deal with it. I couldn't get the OpenOCD integration to work. But I discovered that Eclipse can convert its project format into Makefiles, so with exported Makefiles in hand I got the Hubsan X4 build of BradWii to build.

But before any code could be written, I would need to know the pin mapping for the Mini54 to the peripherals. I traced out the pins mapping to the motors, LEDs, battery voltage monitor, gyro, accelerometer, and radio. I forked BradWii on github and made changes to the Hubsan X4 config and support sources to work with that pin map. Along the way I added a target in the main Makefile to erase flash and call OpenOCD for flashing.

Good news is the LEDs blink on power up and change pattern when the TX is turned on, so at least the RX section and the LEDs work. Bad news is that's all it can do right now.