Klipper KP3S 3.0

##Changes from upstream

• Fork of nehilo's klipper config with adjustments for Titan extruder

• The config is set up for connecting a 3d Touch sensor additionally to the default z endstop. The3D touch sensor pin is connected to the Z+ connector on the main board. In this config Homing is done with the z -endstop and the 3d-touch sensor is used only for probing.

• This config uses an dropin replacement for the LCD-PCB to drive a ssd1306 display with klipper. See additional GPIOs for details.

• Tested on a KP3S 3.0 with GD32F303 MCU. If your motion controller has an original STM32F103 you probably have to untick "Disable SWD at startup" when building the firmware.

• The KP3S 3.0 running this klipper configuration has received some hardware modifications. Using this config on a stock KP3S 3.0 might require revertig certain commits. See hardware [modifications section] below for details.

Additional GPIOs

The KP3S' touch screen is of no use when running Klipper firmware. The PCB holding the display can be replaced a custom PCB to expose additional GPIOs (including SPI) so more sensors, steppers or a Klipper-compatible display and rotary encoder can be attached. Design for a PCB exposing all available extra pins in the aperture of the housing where the touch screen resides can be found in this repo.

Firmware build

Follow the default klipper build instructions

cd ~/klipper

make menuconfig

menuconfig parameters:

                  Klipper Firmware Configuration
[*] Enable extra low-level configuration options
    Micro-controller Architecture (STMicroelectronics STM32)  --->
    Processor model (STM32F103)  --->
[ ] Only 10KiB of RAM (for rare stm32f103x6 variant)
[*] Disable SWD at startup (for GigaDevice stm32f103 clones)
    Bootloader offset (28KiB bootloader)  --->
    Clock Reference (8 MHz crystal)  --->
    Communication interface (Serial (on USART3 PB11/PB10))  --->
(250000) Baud rate for serial port
[*] Optimize stepper code for 'step on both edges'
(!PC6, !PD13) GPIO pins to set at micro-controller startup

make 

Make sure to run the following script to add some magic bytes so the firmware can be flashed.

./scripts/update_mks_robin.py out/klipper.bin out/Robin_nano.bin

Copy the resulting file to the SDcard, insert it into the KP3S and switch it on. After a successful firmware update the file on the SDcard will be renamed to ROBIN_NANO.CUR.

Hardware modifications

Separate control of heatbreak and part cooling fans (since d58fd09)

For separate control of heatbreak and printed part via PWM, the part cooling fans are connected in parallel to the regular fan connector (Fan [PB1]), while the heatbreak cooling fan is attached to the unused heater connector (HE1 [PB0]).

Enabled stepper UART (since c581bc7)

To use stepper driver configuration via UART a bit of light soldering and modifying the stepper jumpers is necessary.

Close UART pin solder brigde

First close the solder bridges for the stepper drivers you want to configure via UART.

axis	jumper	gpio
E0	JP_M1	PA10
E1	JP_M2	PA11
X	JP_M3	PA5
Y	JP_M4	PC13
Z	JP_M5	PC7

The solder brigde locations on the motion controller are highlighted below.

Set Jumpers

The following parameters apply to the MKS TMC2225 stepper driver.

Next the stepper config jumpers need to be set correctly

Jumper locations below the stepper driver:

========
 (C) ABC        AA = M0
     ABC        BB = M1
========        CC = UART

This klipper config is based on the following jumper settings for all active steppers (E0,X,Y,Z):

jumper	state
AA	jumper
BB	jumper
CC	no jumper

Background on jumper config

jumper	stepper driver pin
AA	M0
BB	M1
CC	UART

AA	BB	microsteps
0	0	4
1	0	8
0	1	16
1	1	32

CC	UART
0	enabled
1	disabled

0 = jumper open 1 = jumper closed

Config Files

 -bed.cfg
 -bltouch.cfg
 -display.cfg
 -extruder.cfg
 -fan.cfg
 -macros.cfg
 -printer.cfg
 -stepper.cfg
 -thermistor.cfg
 -tmc.cfg