[Paparazzi-devel] ArduIMU update

[Martin Mueller]

Hi,

have committed some ArduIMU changes to 
https://github.com/martinmm/paparazzi for review.

It is based on ArduIMU v1.7 and fixes the main issue which was printing 
serial data while in I2C interrupt, also includes Steves fixes. 
Additional features are running at 60Hz, having the possibility to use 
the Paparazzi ROLL_RATE loop and transferring the gps data as it is 
received rather than at a constant, non synchronized rate. The v1.7 uses 
gps 3D speed for centrifugal correction whereas the v1.8.2 uses 2D 
speed. Premerlanis paper is a little vague on that but I would think 
that 3D should be more precise when climbing/descending. Maybe 2D is 
used as simple gps receivers don't have 3D speed?

An example airframe file is at mm/fixed-wing/fw_ins_arduimu.xml It 
controlled a Funjet in 55m circles climbing 6m/s nicely.

Next step is to move the calculation over to the LPC/STM using 
Christophes code. The Arduino will then only do AD converting and 
averaging (at a higher and more steady rate).

The Wiki says that the I2C queue length should be increased and the I2C 
clock rate reduced. Both does not make sense to me, sounds a little 
magic. What issues were solved with that?

Martin