BrushedBipolar PWM problem

Not sure if its a bug or setting problem, rover is configured as skid steer type, if MOT_PWM_TYPE sets to normal, after power on and arm, servo1 and servo3 pwm output start with trim value, and range from min to max, no problem.
However, if change from normal to BrushedBipolar, after power up, servo output will change to min 1000, trim 1000, max 2000, regardless whatever I set and saved previously. If I then change min trim max value to different numbers, servos will work as expected, but after another power off and on, all settings lost.
I’m using rover 4.1.0 rc2 and updated to latest 4.2.0 dev, both not working properly.
Set mot type to normal will change output pwm freq to about 50 hz, and duty cycle within a small range. BrushedBipolar can have full duty cycle from 0 to 100% and pwm freq changeable from 1k and 20k, which meet the requirements of some PWM to analog converters
Managed to download the .bin file but can’t upload due to size?(file less than 1M). let me know if need more info.



I don’t know if it is related but @iampete recently added this fix to “latest” but it isn’t included in Rover-4.1.

I guess you could test if this resolves the issue by temporarily loading “latest” on the vehicle (Press Ctrl-Q on MP’s Firmware Install screen).

Thank you Randy for the info, the link you provided looks like similar problem related to brushed motor configuration.
I already tried latest 4.2.0 dev firmware with no good. For now I have to use Lua to initialise those parameters after each reboot.


OK. By the way, what values for min, trim and max do you need to use for the motors to work?

Around 1000,1400,1800. at 1000 servo output pwm duty cycle is zero.
Now the problem is, when power on, servo pwm output is zero, the bipolar brushed motor and rover will run reversly until arming, then the PWM set to 1400 neutral and rover will stop. This may cause danger with unwanted rover movement, not sure if you have any suggestions.


Ok, I understand. So it does seem like our Brushed BiPolar output isn’t working properly. In the wiki it also says,

“Brushed BiPolar” is for brushed motor drivers that, a bit like “Normal” pwm interpret a low PWM values for reverse, a high PWM value for forward

I’ve raised an issue to fix this but I can’t immediately promise when one of us will sort it out. hopefully it won’t be too long.

I cant reproduce this on master. Would be great if you could upload that log somewhere and drop a link here.

Fix here:

With the help of the log I was able to track it down. I could not reproduce in the simulator because it is related to the BHeli code that is only used on real hardware.