Retool A2

Retool is a USB based tool head that works well with Recore. It has

• 1 TMC2209 stepper motor driver for an extruder
• 1 ADXL343 accelerometer for input shaping
• 1 Mosfet for a heater
• 1 Input for thermistor
• 3 Fan outputs with tach feedback
• 1 Peltier cooling output
• 1 inductive probe input
• 1 Neopixel output
• 2 End stop inputs

Pinout diagram

Name	GPIO	Number	Name	Bank and pin	Number	Name	Bank and pin	Number
STEP	GPIO6	6	END STOP 0	PH4	228	OC-ALERT	PF6	166
DIR	GPIO5	5	END STOP 1	PH5	229	OC-RESET	PF4	164
ENN	GPIO10	10	END STOP 2	PH6	230	EN-HP	PF5	165
CLK	GPIO8	8	END STOP 3	PH7	231	UC-INT-1	PG3	195
DIAG	GPIO9	9	END STOP 4	PH8	232	UC-NRST	PG4	196
STEP 5	PL9	9	END STOP 5	PH9	233	UC-BOOT	PG5	197
STEP 6	PL10	10	GAIN-ENABLE-T0	PD4	100	ES-EN-12V	PF0	160
STEP 7	PL11	11	GAIN-ENABLE-T1	PH11	235	EN-THERMISTORS	PF1	161
DIR 0	PE8	136	GAIN ENABLE T2	PE17	145	EN-ENDSTOPS	PF2	162
DIR 1	PE9	137	GAIN ENABLE T3	PB2	34	USR-BTN	PB3	35
DIR 2	PE10	138	PU-ENABLE-T0	PG10	202	USR-PIN	PF3	163
DIR 3	PE11	139	PU-ENABLE-T1	PG11	203	SBU1	PC0	64
DIR 4	PE12	140	PU ENABLE T2	PG12	204	SBU2	PC2	66
DIR 5	PE13	141	PU ENABLE T3	PG13	205
DIR 6	PE14	142	OFFSET-T0	PG0	192
DIR 7	PE15	143	OFFSET-T1	PG1	193
STEP DIAG 0	PE0	128	OFFSET-T2	PG3	194
STEP DIAG 1	PE1	129	OFFSET-T3	PG8	200
STEP DIAG 2	PE2	130	STEPPER UART 0-3	PE16	144
STEP DIAG 3	PE3	131	STEPPER UART 4-5	PD24	120
STEP DIAG 4	PE4	132	STEPPER UART 6	PD2	98
STEP DIAG 5	PE5	133	STEPPER UART 7	PD3	99
STEP DIAG 6	PD0	96	STEPPERS ENABLE	PL12
STEP DIAG 7	PD1	97

Wire diagram

3D model

3D model for using Retool A2 with Voron 2.4/Stealthburner https://www.printables.com/model/1190587-voron-24-retool-a2-holder

Klipper config

[mcu retool]
serial: /dev/serial/by-id/usb-Klipper_rp2040_E661AC8863905924-if00

[static_digital_output retool_led]
pins: retool:gpio2

[output_pin fan_r_1]
pin: retool:gpio1

[output_pin fan_r_2]
pin: retool:gpio12

[output_pin fan_r_3]
pin: retool:gpio21

[tmc2209 extruder3]
uart_pin: retool:gpio7
uart_address: 0
run_current: 0.500
hold_current: 0.500
sense_resistor: 0.1
stealthchop_threshold: 250

#endstop_pin: retool:gpio4
#enable_pin: !retool:gpio10
#rotation_distance: 40
#microsteps: 16
#position_endstop: 0
#position_max: 200
#homing_speed: 20.0

[extruder3]
step_pin: retool:gpio6
dir_pin: retool:gpio5
heater_pin: retool:gpio0
sensor_type: EPCOS 100K B57560G104F
sensor_pin: retool:gpio28
rotation_distance: 40
microsteps: 16
nozzle_diameter: 0.400
filament_diameter: 1.75
control: pid
pid_Kp: 22.2
pid_Ki: 1.08
pid_Kd: 114
min_extrude_temp: 30
min_temp: -272
max_temp: 300

[verify_heater extruder3]
check_gain_time: 2400

[adc_temperature retool_fan_current_0]
temperature1: 0
voltage1: 0
temperature2: 33
voltage2: 3.3

[temperature_sensor retool_fan_current_0]
adc_voltage: 3.3
sensor_pin: remote:gpio29
sensor_type: remote_fan_current_0
max_temp: 2.0
gcode_id: RemoteFanCurrent0

[adxl345]
cs_pin: remote:gpio25
spi_bus: spi1c

[resonance_tester]
accel_chip: adxl345
probe_points:
    100, 100, 20  # an example
    
[probe]
pin: remote:gpio22
#--------------------------------------------------------------------
x_offset: 0
y_offset: 25.0
z_offset: 0	
speed: 10.0
samples: 3
samples_result: median
sample_retract_dist: 3.0
samples_tolerance: 0.01
samples_tolerance_retries: 3

# Set this high to use GPIO20 as high frequency input
[static_digital_output Relit_direction]
pins: !remote:gpio19

[neopixel relit]
pin: remote:gpio20
chain_count: 12


[fan peltier]
pin: remote:gpio3
max_power: 0.1
cycle_time: 0.00001 #0.01
hardware_pwm: True

serial: /dev/serial/by-id/usb-Klipper_rp2040_E66368651B257D22-if00

[static_digital_output remote_led]
pins: remote:gpio2

[static_digital_output nepixel_dir]
pins: !remote:gpio19

[fan]
pin: remote:gpio21
tachometer_pin: remote:gpio23
cycle_time: 0.10

[fan_generic peltier]
pin: remote:gpio3
hardware_pwm: True
cycle_time: 0.000001

[heater_fan hotend_fan]
pin: remote:gpio1
heater: extruder
heater_temp: 50.0

[tmc2209 extruder]
uart_pin: remote:gpio7
uart_address: 0
run_current: 0.800
hold_current: 0.500
sense_resistor: 0.1
stealthchop_threshold: 0

[extruder]
step_pin: remote:gpio6
dir_pin: remote:gpio5
enable_pin: !remote:gpio10
heater_pin: remote:gpio0
sensor_type: ATC Semitec 104GT-2
sensor_pin: remote:gpio28
##  Update value below when you perform extruder calibration
##  If you ask for 100mm of filament, but in reality it is 98mm:
##  rotation_distance = <previous_rotation_distance> * <actual_extrude_distance> / 100
##  22.6789511 is a good starting point
rotation_distance: 22.6789511   #Bondtech 5mm Drive Gears
gear_ratio:  50:10              #BMG Gear Ratio
microsteps: 16
nozzle_diameter: 0.800
filament_diameter: 1.75
control: pid
pid_Kp=28.278
pid_Ki=1.611
pid_Kd=124.070
min_extrude_temp: 15
min_temp: -273
max_temp: 500
pressure_advance: 0.03
##  Default is 0.040, leave stock
pressure_advance_smooth_time: 0.040

[adc_temperature remote_current]
temperature1: 0
voltage1: 0
temperature2: 10
voltage2: 1.0

[temperature_sensor remote_current]
adc_voltage: 3.3
sensor_pin: remote:gpio29
sensor_type: remote_current
max_temp: 3.0

[temperature_sensor remote_mcu]
sensor_type: temperature_mcu
sensor_mcu: remote

[adxl345]
cs_pin: remote:gpio25
spi_bus: spi1c

[resonance_tester]
accel_chip: adxl345
probe_points:
    125, 125, 20
    
[probe]
pin: remote:gpio4
x_offset: 0
y_offset: 25.0
z_offset: 0
speed: 10.0
samples: 3
samples_result: median
sample_retract_dist: 3.0
samples_tolerance: 0.01
samples_tolerance_retries: 3

[neopixel relit_head]
pin: remote:gpio20
chain_count: 4
initial_RED: 1.0
initial_GREEN: 1.0
initial_BLUE: 1.0

Klipper firmware compilation

The unit comes with firmware pre-installed. If you want to upgrade the firmware, these are the steps to reproduce. This can be done directly from Recore, or from a regular computer. If the device ID doesn't match, the board is not in DFU mode, and needs to be manually started that way. Use a paperclip or some wire, unplug the USB of the device, short the two round pads on the back of the PCB and plug in the USB. At that point the RP2040 will be in DFU mode, allowing it to be flashed.

cd /home/debian/klipper
cp test/configs/rp2040.config .config
make olddefconfig
make -j
make flash FLASH_DEVICE="2e8a:0003"

After that, the board should be visible as OpenMoko, Inc. rp2040

Enter boot mode from the command line

cd /home/debian/klipper/scripts
python3 -c 'import flash_usb as u; u.enter_bootloader("<DEVICE>")'
Entering bootloader on <DEVICE>

<DEVICE> is typically "/dev/ttyACM0" or similar.