Getting Klipper to run on Ender3 hardware

Hello I was looking for a new board for my first revision Ender 3 which used old Creality v1.1.4 board. Of course my first choice was SKR Mini E3 v3 but then I found FYSETC Cheetah v2 which has a few advantages in my opinion. I want ahead and bought one.

I'm trying to get Klipper to run on my machine but I noticed the provided configuration files are not 100% correct for Ender3. I had to make a few changes:

@@ -1,129 +1,195 @@
 [mcu]
 ## Obtain mcu value by "ls -l /dev/serial/by-id/"
-serial: /dev/serial/by-id/usb-Klipper_stm32f401xc_4C004E000C51383336383937-if00
+serial: /dev/serial/by-id/usb-Klipper_stm32f401xc_150036001951383336383937-if00

 [stepper_x]
 step_pin: PC0
-dir_pin: PC1
+dir_pin: !PC1
 enable_pin: !PA8
 rotation_distance: 40
 microsteps: 16
 endstop_pin: ^PB4
 position_endstop: 0
-position_max: 200
+position_max: 240
 homing_speed: 50

 [tmc2209 stepper_x]
 uart_pin: PA3
 tx_pin: PA2
 uart_address: 0
 run_current: 0.800
 hold_current: 0.500
 stealthchop_threshold: 250

 [stepper_y]
 step_pin: PC14
 dir_pin: !PC13
 enable_pin: !PC15
 rotation_distance: 40
 microsteps: 16
-endstop_pin: ^PB3
+endstop_pin: ^PC8
 position_endstop: 0
-position_max: 200
+position_max: 240
 homing_speed: 50

 [tmc2209 stepper_y]
 uart_pin: PA3
 tx_pin: PA2
 uart_address: 2
 run_current: 0.800
 hold_current: 0.500
 stealthchop_threshold: 250

 [stepper_z]
 step_pin: PB9
 dir_pin: PB8
 enable_pin: !PC2
 rotation_distance: 8
 microsteps: 16

endstop_pin: ^PB1
position_endstop: 0
position_max: 250

 [tmc2209 stepper_z]
 uart_pin: PA3
 tx_pin: PA2
 uart_address: 1
 run_current: 0.800
 hold_current: 0.500
 stealthchop_threshold: 5

 [extruder]
 step_pin: PB2
 dir_pin: !PA15
 enable_pin: !PD2
-rotation_distance: 33.500
+rotation_distance: 33.683
 microsteps: 16

 nozzle_diameter: 0.400
 filament_diameter: 1.750
 heater_pin: PC6
 sensor_type: EPCOS 100K B57560G104F
 sensor_pin: PC4
 control: pid
 pid_kp: 21.527
 pid_ki: 1.063
 pid_kd: 108.982
 min_temp: 0
 max_temp: 250

 [tmc2209 extruder]
 uart_pin: PA3
 tx_pin: PA2
 uart_address: 3
 run_current: 1.0
 hold_current: 0.500
 stealthchop_threshold: 5

 [heater_bed]
 heater_pin: PC7
 sensor_type: EPCOS 100K B57560G104F
 sensor_pin: PC5
 control: pid
 pid_kp: 54.027
 pid_ki: 0.770
 pid_kd: 948.182
 min_temp: 0
 max_temp: 130

 #fan for printed model FAN0
 [fan]
 pin: PA14

 #fan for hotend FAN1
-#[heater_fan my_nozzle_fan]
-#pin: PA13
+[heater_fan hotend_fan]
+pin: PA13
+heater: extruder
+heater_temp: 50.0
+
+#fan for mainboard FAN2
+[fan_generic mcu_fan]
+pin: PA1

 [printer]
 kinematics: cartesian
 max_velocity: 300
 max_accel: 3000
 max_z_velocity: 5
 max_z_accel: 100

 [board_pins]
 aliases:
     # EXP1 header
     EXP1_1=<5V>,  EXP1_3=<RST>, EXP1_5=PA7,  EXP1_7=PA4,  EXP1_9=PA5,
     EXP1_2=<GND>, EXP1_4=PC3,   EXP1_6=PC11, EXP1_8=PC10, EXP1_10=PA6,

     # EXP2 header
     EXP2_1=<5V>,  EXP2_3=PB7, EXP2_5=PB14, EXP2_7=PB12, EXP2_9=PC12,
     EXP2_2=<GND>, EXP2_4=PB6, EXP2_6=PB13, EXP2_8=PB15, EXP2_10=PC9,

     # EXP3 header
     EXP3_1=PC9,  EXP3_3=PC10, EXP3_5=PC11, EXP3_7=PB12, EXP3_9=<GND>,
     EXP3_2=PC12, EXP3_4=PB14, EXP3_6=PB13, EXP3_8=PB15, EXP3_10=<5V>
     # Pins EXP1_4, EXP1_8, EXP1_6 are also MISO, MOSI, SCK of bus "spi2"

+[display]
+lcd_type: st7920
+cs_pin: EXP3_7
+sclk_pin: EXP3_6
+sid_pin: EXP3_8
+encoder_pins: ^EXP3_5, ^EXP3_3
+click_pin: ^!EXP3_2
+
+[output_pin beeper]
+pin: EXP3_1

This is a good starting point if someone is struggling to get Ender3 hardware to work properly.

I have multiple isues though:

I can't get internal MCU temperature sensor to work. Since Ender3 has additional fan for the mainboard I'd like to run it only when it gets too warm. I tried configuring custom temperature sensor:
```
[temperature_sensor mcu_temp]
sensor_type: temperature_mcu
sensor_mcu: mcu
min_temp: 0
max_temp: 100
```

But I get MCU 'mcu' shutdown: Not a valid ADC pin error.

Can't get BLTouch to work - this is the most frustrating one. I'm using v3.0 3D Touch clone on my setup and it was working properly with previous board. Now with Cheetah v2 Klipper can't control the probe, it doesn't react to any BLTOUCH_DEBUG commands. My config for BLTouch looks like this:
```
[bltouch]
sensor_pin = ^PB1
control_pin = PA0
x_offset: -45
y_offset: -8
z_offset: 3.2
samples: 2
speed: 10.0
probe_with_touch_mode: true
stow_on_each_sample: false
```

Any idea how to deal with these issues, especially BLTouch?

FYSETC / FYSETC-Cheetah-v2

Getting Klipper to run on Ender3 hardware #4