Arduino Due based TX

[humblehacker]

Hello,
I am relatively new to the RC world though I have plenty of experience working with Arduino etc... I recently upgraded from a Spektrum DX5e to a Turnigy 9xR Pro and I noticed that the 9xR Pro is based on the same chipset as the Arduino Due (ATSAM3x8E). I'm wondering if it would be possible to flash the Arduino Due with OpenTX or another 9xR Pro-compatible firmware and use it with the shell, pots, switches etc... from the Dx5e? If necessary I could cut an opening for an Arduino LCD screen and any extra switches etc...

I've tried searching for "Arduino Due, Dx5e, OpenTX" etc... but the only information I could find were a few threads on this forum that seemed to indicate that it should be possible. So if anybody is aware of
A,Whether or not it can actually be done
and/or
B.where I could find documentation on pinouts, firmware etc...
I would greatly appreciate your assistance!

In case anybody is wondering why I would want to DIY my own 9xr Pro when I already have one, it is because I'm working on a long term experiment that involves building an aircraft with as many DIY components as possible. So in addition to homebrewing a Naze32 FC with an STM32+10DOF sensors I would eventually like to homebrew things like the RX and TX using NRF2401 modules and Arduino. To ensure I don't go crazy in the process however, I'll be building another quadrotor in parallel that uses off-the-shelf components like a Flip32+, and OpenLRSng RX/TX modules with the 9Xr Pro. That way I can rely on there being plenty of documentation to help me get my bearings. Eventually I hope to document the entire process so hopefully others can build their own homebrew versions without as much hassle.

If anybody can help or is interested in either the Arduino Due+Dx5e hack or the FUll Homebrew project please do let me know through this thread!

Also if anybody would like to know more about the DIY methods I mentioned earlier here are the links-
DIY Naze32- http://www.rcgroups.com/forums/showthread.php?t=2154329
DIY OpenLRSng- http://www.rcgroups.com/forums/showthread.php?t=2114859

[MikeB]

The 9XR-PRO uses the ATSAM3S8, while the DUE uses a '3X8. There are some differences which affect the low level drivers.
I was looking at using a DUE as an upgrade for the normal 9X, but it is missing too many things like RTC, SD card, audio amp. and external EEPROM.
There is a new addon board for the 9X in design, that may be more suitable as it includes this things.

Mike.

[humblehacker]

Thank you for the info on drivers etc... Coincidentally, I was just reading about the Due's support for RTC, EEPROM etc... in this thread (http://forum.arduino.cc/index.php?topic=329101.new#new) that compares the DUE to the new Arduino Zero, which is also based on the 32bit SAM but in a smaller footprint ala the original UNO. The Zero also includes some of the features you cited the Due as lacking such as an RTC, virtual EEPROM etc...(though one of the posters claims that the DUE does in fact have an RTC, I think most people agree it is unusable...) The Zero's MCU is not a SAM3-- however, but rather the newer SAM-D21 (http://www.atmel.com/images/atmel-42181 ... asheet.pdf) so I don't know if this complicates matters even more so...

Personally, I think Arduino missed the boat on 32bit by not releasing the Due or Zero in the "Pro Mini" footprint used by early DIY flight controllers like MultiWii and ArduPilot. Instead, current generation FCs tend to use the STM32, which may pack a more powerful punch but lacks the enormous resources of user-contributed libraries developed for the Arduino and is far less versatile as a result IMHO...

Another question I have about the Zero is whether or not it supports a long-neglected but potentially powerful feature of the DUE and MegaADK, in the form of Android Accessory support. For example, perhaps a Due/Zero with ADK support could be combined with a full featured android app like the EZ-GUI to create an Android-based, Software-Defined, RC Transmitter? Such a device would require a far smaller footprint as the display, telemetry, mission planner etc... could all be done on the phone/tablet while the Due/Zero could run a fork of OpenTX to control the pots and switches. Rather than bluetooth, which has serious limitations in outdoor flight modes, the Due/OpenTX could transmit in 433Mhz via OpenLRSng. A similar method is used by the Crazyflie nano-drone, which uses a USB-enabled version of the NRF24L01 tranceiver connected via a USB OTG cable. Of course the CF is only meant to be used indoors, but OpenLRSng utilizes a much higher-powered form of the NRF24 to achieve far greater range outdoors.

[MikeB]

The SAM-D21 is rather smaller in terms of flash and RAM than the SAM3 devices, and only has a 10-bit DAC I see.
You may wish to follow progress of the 9Xtreme board here: viewtopic.php?f=95&t=7182&hilit=9xtreme.
It is currently being prototyped.

Mike.