Copter-3.6.10-rc2 available for beta testing

Copter-3.6.10-rc2 has been released for beta testing and should be available from the various ground stations’s within the next couple of hours (if using MP then click the “Beta Firmwares” link on the “Install Firmware” screen).

This release has the following changes vs 3.6.10-rc1 (ReleaseNotes):

  1. mRobotics ControlZeroF7 board support
  2. Motor Test fixed by removing delay that triggered CPU Watch Dog

This release also includes all the changes in 3.6.10-rc1:

  1. EKF improvements:
    a) learns biases even for inactive IMUs
    b) EKF uses earth magnetic field model to reduce in-flight compass errors
    c) EKF switches to first healthy IMU when disarmed
    d) IMU fix for dropped samples during high CPU usage
    e) Optical flow fusion start fix when some gyros disabled
  2. Ublox F9 GPS support
  3. Integrated CPU Watch Dog for STM boards including logging of reset reason
  4. ChibiOS I/O firmware for ChibiOS builds to support Spektrum binding
  5. Auxiliary switch changes always logged
  6. CUAVv5 Nano LED fix
  7. Solo Gimbal fix when some gyros disabled

Thanks in particular to @dkemxr and @winstonsaz who uncovered issues with -rc1!

This an important release including a number of EKF improvements so any testing and feedback provided is greatly appreciated!


My congratulations, now it works faster than in the previous versions, in previous versions there was a delay of approximately 1.5 seconds before starting the motor, but in this version it does immediately, I have not noticed any delay.

Thanks Randy.


@winstonsaz, great, thanks for the feedback!

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Indeed, Motor Test is now working with my PixRacer!


Nice! Thanks for the Bosch IMU driver backport with ControlZeroF7 board support.

I’m having issues using a pixracer with an external BMI088: with master (updated to commit) it works, using this version (3.6.10-rc2) it fails to initialize the INS driver. I’ve used the same hwdef.

Has spektrum binding been non-functional since implementing ChibiOS?

@ekliptiko, Copter-3.6.x is available on both NuttX and ChibiOS. My understanding is that the Spektrum binding has been fine on the NuttX builds but wasn’t included in the ChibiOS build until this latest version (3.6.10).

Well that might explain why I’ve been having no success trying to bind a yuneec rx and TX through mavproxy.

I’m thinking about releasing this version (Copter-3.6.10-rc2) as the official version as early as tomorrow so any other feedback or testing results (good or bad) that people have is greatly appreciated.

Thanks @rmackay9!
The only thing strange to me is that the BMI088 driver fails to initialize while in master it works.

@guglie, it looks like the BMI088 driver was created in Feb which is long after Copter-3.6 was released. In general we don’t backport everything from master into stable releases. Instead we only backport bug fixes and the occasional enhancement if it’s very useful to a lot of users and also low risk.

We are hoping to start beta testing of Copter-3.7.0 within 4 weeks and this will include the new driver.

Hello. Recently I’m using loiter mode indoors with a optical flow(CX-OF), the newest stable version(3.6.9) doesn’t work well and neither does this version(Copter-3.6.10-rc2). My pixhawk refused to switch to loiter. But V3.7.0-dev (5b5f5823) work perfectly.

My previous post is Flight mode change failed when use CX-OF(optical flow) , and the test logs for this version(Copter-3.6.10-rc2) is as below:
Calibrating the (200.1 KB)
fail to switch to (189.8 KB)

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@guglie, I discussed this quickly with Tridge and he asked whether you were connecting with I2C or SPI? My guess is that the SPI BMI088 driver is available but perhaps not the I2C version.


The only reason I can think of that 3.7.0-dev would work better than 3.6.x is that we made a small improvement to EKF2 to allow it to handle higher updates rates of many sensors. The CX-OF updates at 25hz which is technically above the previously acceptable 20hz limit.

Of course you’re running the ChibiOS version of Copter-3.6.10? It probably doesn’t matter but ChibiOS’s timing is better than NuttX (i.e. it runs more smoothly - i.e. the main loop runs at more regular intervals - it’s almost perfect actually).

Yes, I have the same problem

@chongshuhuo, can you be more specific about which problem you have seen?

Thank you very much. After I reduce the frequency of the opticalflow by a little trick, pixhawk with 3.6.10 can hold position. Furthermore, chongshuhuo who asked after me is my friend and his problem is the same as mine.

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Thanks @rmackay9, sorry I asked only because I saw ControlZeroF7 board support in the release notes (and ControlZeroF7 has BMI088).
Yes, my BMI088 is connected with SPI, but I found the problem:
Copter-3.6 uses a switch inside AP_InertialSensor to initialize driver backends, while in master this is handled nicely in hwdef so to make it work in 3.6.10 I just needed to add the following lines to the pixracer case


Ah, nice analysis!