|Subject:||Re: [Paparazzi-devel] motor command error on hexa------work arround progress|
|Date:||Mon, 25 Mar 2013 14:55:18 +0100|
Hi,MKK_I2C_SCL_TIME is only valid on LPC21xx.For the STM32, use the more generic <define name="I2C1_CLOCK_SPEED" value="400000"/> as I wrote in the previous email.Also, the "fix" from Sergey certainly helps to not accidentally drop transactions because the queue is full.But if you can't send all transactions (for all 6 or 8 motors) within one 512Hz cycle, it is not good to rely on this as you will send transactions with old commands.You can check that by downlinking the value actuators_mkk.submit_err_cnt variable, which counts the number of failed I2C transaction submits.It would be much better to really explicitly only send e.g. 4 transactions for one (symmetric) set of motors in once cycle and the other 4 in the next.Cheers, FelixOn Mon, Mar 25, 2013 at 2:45 PM, Eduardo lavratti <address@hidden> wrote:
changing the scl time i change the i2c clock frequency right ?
Well, i changed the scl time from 20 to 50 and 150 and the i2c clock continue away the same 48khz.
i use this config to change scl time
<define name="MKK_I2C_SCL_TIME" value="50"/>
i to some mistake ?
Subject: Re: [Paparazzi-devel] motor command error on hexa------work arround progress
I updated the my local copy yesterday. ( i am using master)
Thank for you considerations.> To: address@hidden
> Date: Mon, 25 Mar 2013 09:14:34 +0100
> From: address@hidden
> Subject: Re: [Paparazzi-devel] motor command error on hexa------work arround progress
> Hi Eduardo!
> If the problem is still actuall, try to checkout the latest
> actuators_mkk.c file from the master branch.
> I've added the i2c submission control, so the actual queue length could be
> leaved unchanged.
> I've also experienced problems with 8 mkk controllers, they a very
> sensitive to the bus speed. With the 400kHz there going to be the bus
> errors anyway. I've had problems with 8 mkk sometimes even with the bus
> speed about 60kHz. So try to let your bus speed down. But when you let
> your bus speed down, and it is not sufficient to control all the motors
> once per periodic time, the queue length increase is not going to help. So
> then you have to use the fixed actuators_mkk.c file.
> But anyway, I've experienced a crash with the stock MK autopilot because
> of i2c errors problem, so imho the solution with more than 6 mkk
> controllers is not reliable enough. I wouldn't recommend that.
> Paparazzi-devel mailing list
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