[Marlin 2.1.2.1] BTT Octopus V1.1 - Issue with controlling fans

Hi @all,

This is my first post in a forum since 8 years of 3D printing. I have been able to find a solution to all previous problems, but this time I have reached the limit of my knowledge... So, I have a problem (the most commonly used beginning of a conversation in a forum)...

I have BTT Octopus V1.1 STM32F446ZE_btt (512K).

This board has 6 FAN ports, and these drive me crazy...

I use no BTT Touch, but the 12864.

Here is the problem:

If I set the fan speed over the display:

Fan Speed for fan 1 -> All OK
Fan Speed for fan 2 -> fan 1 will be set
Fan Speed for fan 3 -> fan 1 will be set
Fan 4 not used
Fan Speed for fan 5 -> All OK
Fan Speed for fan 6 -> All OK
If I set with M106 Px Sxx:

The same happens with fans 1-3. Anytime fan 1 will be set, regardless of which fan was called. Fans 5 and 6 cannot be controlled by M106 – they do nothing.

The problem seems to be that the pins are protected, regarding M43:

PIN: PA8          M42 P8            FAN_PIN                                 protected
PIN: PE5          M42 P69          FAN1_PIN                               protected
PIN: PD12        M42 P60          FAN2_PIN                               protected
PIN: PD13        M42 P61          FAN3_PIN                               protected
PIN: PD14        M42 P62          FAN4_PIN                               protected
PIN: PD15        M42 P63          FAN5_PIN                               protected

In Configuration_adv.h no AutoFan is defined:

#define E0_AUTO_FAN_PIN -1
#define E1_AUTO_FAN_PIN -1
#define E2_AUTO_FAN_PIN -1
#define E3_AUTO_FAN_PIN -1
#define E4_AUTO_FAN_PIN -1
#define E5_AUTO_FAN_PIN -1
#define E6_AUTO_FAN_PIN -1
#define E7_AUTO_FAN_PIN -1
#define CHAMBER_AUTO_FAN_PIN -1
#define COOLER_AUTO_FAN_PIN -1

#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
#define EXTRUDER_AUTO_FAN_SPEED 255   // 255 == full speed
#define CHAMBER_AUTO_FAN_TEMPERATURE 30
#define CHAMBER_AUTO_FAN_SPEED 255
#define COOLER_AUTO_FAN_TEMPERATURE 18
#define COOLER_AUTO_FAN_SPEED 255

// Fan configuration
#define FAN_COUNT 6
#define NUM_M106_FANS 6

What could be the problem ?

Attached the complete configuration.h and configuration_adv.h.


Thanks in advanced

// Cheers CR

Edited 1 time(s). Last edit at 02/06/2025 10:23AM by Cumpy Rules.

protected simply means that Marlin controls it, so you can't use M42 on that pin.