E70 Max drone/quadcopter flight
controller with Atmel SAME70
By Thomas Butler, Thomas Butler Technology, Rockford, Illinois
It has been about nine years since I first started working on RC flight controllers. My first design was in 2009 for an Esky Honey Bee helicopter. Some of my first videos (it is a bit shaky and before we had gimbals) can be seen at Rockford Quadcopter on YouTube. My first design was a bit wild with three CPUs (one for each axis) and never made it to production. The difference in the electronics used in my first design and the latest E70 is truly amazing!
First flight controller ©2008 Thomas Butler, Rockford, Illinois
I have been working on this Atmel SAM E70 based controller for over a year. Due to financial reasons it looks like I won’t ever get to the production stage. I am a realist. There is no way I can compete in hardware manufacturing with the Far East juggernaut paying their employees ten cents a day (hello Apple, Inc.). Hardware design is too easy to copy and steal! Therefore, I am releasing the design into the public domain. Anyone is free to copy or modify the design.
The design has all the required elements required to be able to run Pixhawk/ArduCopter, Taulabs, OpenPilot, and other flight controller software. Since the board is NOT a derivative of any open source design, there is no requirement for a derivative someone creates of my design to be released to the public domain. In other words, anyone is free to copy or modify the design without having to post his or her enhancements into the public domain.
In addition, the board has a complete on-board power supply. However, other designers might want to omit the supply and use an off-board circuit. The board has an FFC connector for an off-board IMU that would be in a special vibration isolated mount. The board uses the newer Invensense ICM20608, but can be populated with the ubiquitous MPU6000 instead. The CPU is the 300mhz Atmel SAM E70 that has an M7 core and can run at 300mhz with 2MB of code space memory. This CPU is the next generation of the ARM M4 core used in the STM32F4 CPU of the PixHawk and other flight controllers.
Although the board has on-board gyros and accelerometers, these were only intended to be used to calibrate the sensors on the external IMU which is connected via an Flexible Flat Cable (FFC).
If anything, the design can be a starting point for others looking to use the E70 CPU in some other project.
I have included a spreadsheet which documents all of the pins used.
I am not releasing a PCB layout. Hey, how easy must I make this! The main purpose of releasing the design is for educational purposes. If someone wants to build the actual board (i.e., the Far East juggernaut), they will have to do some work and lay out the PCB! Besides if I released the PCB layout all I would hear about is how I used the “wrong” connectors. This way the designer is free to use whatever connector he or she desires.
If I have the urge, when I have nothing to do, I might post updates to the design periodically, but for the most part, I am done with it. If you have a suggestion about the circuit, feel free let me know about it.
LICENSE: The copyright of the E70 Max flight controller design is hereby released by Thomas Butler and Thomas Butler Technology, Rockford, Illinois into the public domain with no restrictions. Good luck!
KiCad files for the design are available here on GitHub