Kakute F4 mini 5th pwm output problem

after i got the new kakute f4 mini board and flashed 4.1.3 firmware. i try to used the 5th PWM output to control the gimbal. i mapped the radio controller channel8 to sevo5 by setting SERVO5 function as RC8, but no pwm output from M5 pad on the board.
the document says kakute f4 mini support 5 pwm output, what should i do to get the M5 pwm ouput work?

anyone has any idea, thanks in advance.

Why are you using ArduCopter 4.1.3?
Why are you not using ArduCopter 4.1.5?

is that version problem only? i use 4.1.3 because i fly this version for a while and just added gimbal recently.

any problem with my setting?

All you need to know can be found here including the answer to your question:
Kakute F4 Mini Hwdef

Here is the list of issues fixed in 4.1.5 Copter: 4.1.0 issues list · Issue #16478 · ArduPilot/ardupilot · GitHub
Some of those issues have not been fixed in 4.1.3

I updated the firmware to 4.1.5, set servo5 function as RC8, still has no pwm ouput from M5 pad on kakute f4 mini board.

so, what the problem could be?

I guess you missed this in the link I posted:
PWM5 is used for LED output.
PC8 TIM8_CH3 TIM8 PWM(5) GPIO(56) # LED strip

I checked your post

setup for LEDs on chan5

SERVO5_FUNCTION 120
NTF_LED_TYPES 257
SERIAL3_BAUD 115

but ardupilot.org says
The M5 is defaulted to support serial LEDs instead of PWM but can be changed by changing its default function using SERVO5_FUNCTION and supports Dshot.

so i cannot use M5 pwm output by setting SERVO5_FUNCTION=58? there is noway to map RC8 channel to servo5 output?

It makes no mention of this in the Github repository readme.md. It simply says it’s PWM5 is used for LED. Perhaps you have to modify the hwdef and recompile not sure.

kakute F4 mini manual says, M5 and M6 must be resourced to activate the function like below
Type in the following command in the CLI window:
resource MOTOR 5 B06
resource MOTOR 6 B07
timer B06 AF2
timer B07 AF2
dma pin B06 0
dma pin B07 0
save
it seems timer and dma should be configured, is there same code in ardupilot verson?