The Duet3D Toolboard places the control requirements for a direct drive extruder right on the tool. It controls the stepper motor driver, 3 mosfets for heaters and fans, 2 fan tacho inputs, 2 temperature sensor interfaces, filament monitor, Z probe and endstop, using an ARM Cortex M0 processor.

This reduces the number of wires needed to two power wires and two twisted pairs for the CAN bus. In comparison a direct drive extruder tool such as the E3D Hemera would normally need four wires for the stepper motor, two for the heater, three to five for 2 fans, and at least 2 for the temperature sensor: total 11 or more wires. If a filament monitor is wanted, 3 more wires are needed; and if a Z probe is wanted, another 1 to 3 wires, totalling 14 to 17.

To make it easy to connect multiple direct driver extruders in a tool changer or other multi tool machine, we have also designed a Tool Distribution board. This takes power from the PSU and CAN bus from the Duet. It provides 4 power outputs for Toolboards using 2-pin JST VH connectors and 4 CAN connections for Toolboards using 4-pin JST ZH connectors.

Processor	ATSAMC21G18A
Processor features	48MHz ARM Cortex M0+, 256KB Flash, 32KB RAM
Networking/Comms	CAN-FD interconnect to Duet 3 Tool Distribution Board or Duet 3 Mainboard; serial port
On-board stepper driver	1 x TMC2209
Stepper driver features	Up to 1.6A peak current, microstep interpolation from any setting to x256, stall detection, stealthChop2
Heater outputs	1 x extruder heater (up to 5A)
Thermistor/PT1000 inputs	2, optimised for 100K thermistors and PT1000 sensors
Fan outputs	1 x 4-wire and 1 x 3-wire PWM-controlled fans output with tacho wires. Voltage selectable between VIN and 12V.
Inputs/Outputs	3 x on-board I/O connectors for endstop, switches, filament monitor, Z probe. Two push buttons. 1 x footprint for a switch (v1.1) or switch or optical proximity sensor (v1.2)
Endstop or filament monitor inputs	See under Inputs/Outputs
Z probe connector	See under Inputs/Outputs
Power monitoring	VIN voltage reporting
Accelerometer	Integrated LIS3DH accelerometer (v1.1 only)

Stepper driver	Up to 1.6A peak current, 1.1A RMS
Heater output	1 x extruder heater, up to 5A
Input power voltage	12V to 32V
Power input connector rated current	10A maximum, or fused limit (whichever is lower)
Inputs/Outputs	IO_0, IO_2 and IO_3 are 30V-tolerant, IO_1 is 3.3V-tolerant
Fuses	None onboard. Use Duet 3 Tool Distribution Board (5A fitted), or if directly connected to mainboard, use inline fuse holder with 5A fuse.
5V / 3.3V current limit	300mA peak, 50mA continuous (combined 5V and 3.3V total current limit)
12V current limit	800ma total (OUT_1 and OUT_2 pins only, when 12V selected)

• Compatible RepRapFirmware versions: RRF 3.x
• Firmware limitations: See Duet 3 with CAN expansion firmware configuration limitations

The power in screw terminal projects 8.5mm from the top of the PCB. When the JST power connector is fitted, the highest part is the latch on that connector, which at its highest point is nearly 10mm above the PCB surface, although the latch could be cut off if space was critical.

The STEP file is available for [download from Github here](https://github.com/Duet3D/Duet3-Toolboar...).

Click on the image for a larger version

The STEP file is available for download here: https://github.com/Duet3D/Duet3-Toolboar...

Note there is a SOD123 diode soldered on the back of the v1.1 toolboards which should be taken into account when mounting the board. This is included in the STEP file linked above.

Click on the image for a larger version

The STEP file is available here: https://github.com/Duet3D/Duet3-Toolboar...

The tallest components on the board are the screw terminals which project 8.5mm from the top of the PCB. (Note on revision 1.0 the out 2 screw terminal projects 10mm, this is not shown in the step file). When the JST power connector is fitted, the highest part is the latch on that connector, which at its highest point is nearly 10mm above the PCB surface, although the latch could be cut off if space was critical.

The mounting hole spacing has been designed to be compatible with the E3D Hemera extruder.

Here https://miscsolutions.wordpress.com/2020... is a blog detailing how to replace two of the original Bowden tools on an E3D Tool Changer with Hemera tools using tool boards.

A STEP 3D model of each revision of the board is available on github here.

Click on the image for a larger version

Click on the image for a larger version

Click on the image for a larger version

Click on the image for a larger version

• JST ZH: (CAN, v1.0 headers) These are difficult to crimp because they are so small, so Duet3D supply pre-terminated connectors. You can connect longer wires to them by hand soldering or using small size (white) solder sleeves.
• Screw terminals: These are not high current so fitting the wires directly into the screw terminals is fine. Using small ferrules is also fine; Duet3D supply 0.5mm^2 white ferrules.
• We recommend connecting the hot end metalwork to ground on the toolboard via a resistor (10k to 1M Ohm), if it is not grounded through its mounting system. This will prevent the hot end building up static charge, which might otherwise occur as filament is extruded and may then flash over to the tool board thermistor input, causing damage.

Duet 3 Toolboard 1LC provides the following connectors:

Connector (board revision)			Label	Function
v1.1	v1.0	v0.6
1 x 2-pin JST VH			POWER IN, VIN, GND	Two pins for main VIN and GND. VIN power is fused at 5A.
4-pin JST PH	Screw terminal		IO_0	Input/output with +5V power, for endstops, Z-probes. Input is 30V-tolerant
3-pin JST PH	3-pin JST ZH	Screw terminal	IO_1	Input only with +3.3V power, intended for filament monitors. Note: Input is 3.3V-tolerant
3-pin JST PH	3-pin JST ZH	Screw terminal	IO_2	Input only with +5V power, for endstops or tool pickup detection switch. Input is 30V-tolerant
1 x 3-pin footprint	N/A		IO_3	(v1.1 board) Footprint to mount an Omron D2FD-1L30-1T ultra subminiture switch or similar. Example use case is a tool docking confirmation switch.
4-pin JST PH			DRIVER_0	Stepper motor connection
1 x 6-pin JST ZH			SWD	This is for firmware debugging and also provides a backup mechanism to program firmware.
2-pin JST PH	Screw terminal		TEMP_0	Thermistor or PT1000 input. TEMP_0 uses a 16-bit ADC for high resolution reading of PT1000 sensors.
2-pin JST PH	2-pin JST ZH	Screw terminal	TEMP_1	Thermistor or PT1000 input
1 x Screw terminal			OUT_0	High current output intended for extruder heater, maximum current 5A. There is no flyback diode on this output, so if you connect a high-current inductive load, you must use an external flyback diode.
4-pin JST PH	Screw terminal		OUT_1	4-wire fan output (also accepts a 2- or 3-wire fan) intended for use as the print cooling fan. 2A total max current for OUT1 and OUT2 when VIN selected (v1.1 board), 0.8A total max current for OUT1 and OUT2 on 12V. This output is protected by a flyback diode.
				Note On v1.0 boards and earlier, VOUT on OUT_1 and OUT_2 is set to 12V. On v1.1 boards, voltage is selectable between 12V and VIN, using VOUT for OUT_1, OUT_2 pins.
				Note When using a 4-wire fan, the tacho reading is valid at all PWM settings.
3-pin JST PH	Screw terminal		OUT_2	3-wire fan output (also accepts a 2-wire fan) intended for use as the hot end fan. 2A total max current for OUT1 and OUT2 when VIN selected (v1.1 board), 0.8A total max current for OUT1 and OUT2 on 12V. This output is protected by a flyback diode.
				Note On v1.0 boards and earlier, VOUT on OUT_1 and OUT_2 is set to 12V. On v1.1 boards, voltage is selectable between 12V and VIN, using VOUT for OUT_1, OUT_2 pins.
				Note the tacho reading is valid only when running the fan at full speed.
1 x 2-pin KK	N/A		VOUT for OUT_1, OUT_2	(v1.1 board) Voltage select for OUT_1 and OUT_2, between 12V and VIN. On V1.0 boards it is set to 12V. 0.8A total for OUT1 and OUT2 when set to 12V because the maximum output current of the 12V regulator is 1A, and the 5V rail is also derived from that regulator.
2 x Push button			Button 0, Button 1	Buttons can be used to generate triggers. If both buttons are held down at power on, the board will factory reset; CAN address (121) and CAB bus speed (1Mbps) will be reset to defaults.
1 x 4-pin JST ZH			CAN	CAN connector. See CAN section below.

LEDs are provided to indicate the following:

Label	Colour	Function
VIN	Blue	Indicates presence of VIN power (VIN should be externally fused)
5V	Red	Indicates presence of 5V power from on-board regulator
ACT / LED 1	Green	Indicates activity on the CAN-FD bus
STATUS / LED 0	Red	Status LED. See description below

Status LED: In normal use, the red LED flashes slowly in sync with the main board to indicate that it has CAN sync, or flashes continuously and rapidly to indicate that it doesn't. It also flashes startup error codes, for example if the bootloader doesn't find valid firmware on the board. For a list of these error codes see CAN connection

For more information on pin names, see Pin names.

RepRapFirmware 3 uses pin names for user-accessible pins, rather than pin numbers, to communicate with individual pins on the PCB. In RRF 3 no user-accessible pins are defined at startup by default. Pins can be defined for use by a number of gcode commands, eg M574, M558, M950.

The Duet 3 series uses the pin name format "expansion-board-address.pin-name" to identify pins on expansion board, where *expansion-board-address* is the numeric CAN address of the board. A pin name that does not start with a sequence of decimal digits followed by a period, or that starts with "0." refers to a pin on the Duet 3 Mainboard.

Pin location	RRF3 Pin name	Notes
Outputs
OUT_0	out0	5A max output
OUT_1	out1	2A total max current for OUT1 and OUT2 when VIN selected (v1.1 board), 0.8A total max current for OUT1 and OUT2 on 12V.
	out1.tach
OUT_2	out2	2A total max current for OUT1 and OUT2 when VIN selected (v1.1 board), 0.8A total max current for OUT1 and OUT2 on 12V.
	out2.tach
Inputs/Outputs
IO_0	io0.out	5V. 300mA peak total max output, 50mA continuous
	io0.in	30V tolerant
IO_1	io1.in	3.3V tolerant
IO_2	io2.in	30V tolerant
IO_3	io3.in	30V tolerant
TEMP_0	temp0
TEMP_1	temp1
Button 0	button0
Button 1	button1

OUT_0, OUT_1 and OUT_2 are PWM-capable.

The individual IO_x connectors have the following capabilities:

IO #	UART/I2C?	Analog in?	PWM out?	Notes
IO_0	No	Yes	Yes
IO_1	No	No	No	Input only, no ouput pin
IO_2	No	No	No	Input only, no ouput pin
IO_3	No	No	No	Input only, no ouput pin

The Duet 3 Tool Distribution Board is available to simplify the connections to up to 4 Toolboards.

Apply between 12V and 32V to the VIN connector of the Tool Distribution Board. Then connect each tool to 1 of the JST VH terminals.

Each power connection is individually fused.

Connect the 4-pin CAN connector on the Toolboard to one of the corresponding 4-pin connectors on the Tool Distribution Board, using a straight-through cable comprising two twisted pairs. One pair should use pins 1 and 2, the other should use pins 3 and 4. Note, this is not the same as for a CAN cable terminated in 6p4 RJ11 connectors, which by convention connects one twisted pair to the two middle pins and the other to the two outer pins.

It is also possible to connect a Toolboard directly to the Duet 3 Mainboard 6HC, or Duet 3 Mini 5+.

Supply between 12V and 32V to the VIN power connector on the Tool board through a fuse and observing the correct polarity. Inline blade fuse holders are readily available, pick the lowest rated fuse appropriate for your heater and motor current draw.

Duet 3 Mainboard 6HC: Connect the RJ11 socket on the Duet 3 main board to the correct 2 CAN pins on the tool board, and terminate the other 2 CAN pins on the tool board. If using one tool board, connect pins 3 and 4 (the middle 2 pins) of the RJ11 connector on the Duet to pins 4 and 3 of the tool board, making sure you get them the right way round i.e. CAN1_H in the Duet to CANH on the tool board. (Pins 2 and 4 of the tool board are interchangeable, as are pins 1 and 3.) Don't connect anything to pins 2 and 5 of the RJ11 connector on the Duet.

Duet 3 Mini 5+: On the Mini 5+ connect the CAN_FD socket to the 2 CAN pins on the tool board, and terminate the other 2 CAN pins.

This image shows a cable made to connect a Duet 3 Mini to a ToolBoard 1LC

Bridge the solder jumper on the back of the tool board to bring the 120R resistor into the circuit:

Connect a 120R termination resistor between pins 1 and 2 of the connector on the tool board, as shown in the diagram below

All boards in the system must have different CAN addresses. Tool Boards are shipped set to a default CAN address (normally v121, but 10 for some of the initial production run). Therefore, if you have more than one new Tool Board, only one of them must be powered up and connected to the CAN bus. So disconnect power to all but one of them (you can leave the CAN bus connected if it's easier).

The board has two buttons. Button 0 is in the top left corner of the board and button 1 is to the right of it. Between the two buttons are red and green LEDs. In normal use, the red LED flashes slowly in sync with the main board to indicate that it has CAN sync, or flashes continuously and rapidly to indicate that it doesn't. It also flashes startup error codes, for example if the bootloader doesn't find valid firmware on the board.

The buttons can be used to generate triggers in the normal way. Their pin names are "button0" and "button1". The required pullup resistors are enabled automatically on these pins.

The board will do a factory reset if you power it up with both buttons held down. The CAN address will be reset to the default (121) and the CAN bus timing will also be reset to default (1Mbps).

It is recommended to add the following to config.g, before any commands that reference any CAN bus connected expansion boards

G4 S1   ;wait for expansion boards to start

Check that you can communicate with the Tool Board, by sending M115 B121 (if that fails, try M115 B10).

You can reset the CAN-FD bus back to defaults (CAN Address 121, Bus speed 1Mbps) by holding down both buttons and powering up the board).

The firmware filename is Duet3Firmware_TOOL1LC.bin and this needs to be uploaded to the /firmware folder of the SD card on the attached SBC, or the SD card in the Duet 3 main board if it is running in standalone mode. (note for RRF versions prior to 3.3 firmware files were in the /sys directory not the /firmware directory).

Update the firmware by using the M997 B# command, where # is the CAN address of the new board.

CAUTION! On version 0.6 tool boards, the heater and fans on will be turned on when the board is powered up unless valid firmware is loaded. This means that the heater and fans will be on during a firmware update. This isn't normally a problem unless you have a very fast hot end heater, because the firmware update process takes only a few seconds. However, if the firmware update fails, the heater could be left on for an extended period of time. Therefore, when updating firmware, you should either disconnect the heater, or watch the red LED carefully and be ready to turn power off if it doesn't resume flashing in sync with the Duet 3 main board within a few seconds.

• Send command M115 B# to verify that the main board can communicate with the Tool Board, where # is the original CAN address (normally 121)
• Send command M952 B# A## where ## is the new address you want to use. We suggest you use addresses starting at 20 for Toolboards. So for the first Tool Board, if your new CAN board was at address 121, send M952 B121 A20.
• Power the system down and up again, or send M999 B121. This will cause the Tool Board to restart with the new address.
• Send command M122 B20 (or whatever address you chose) to verify that you can communicate with the Tool Board at its new address
• You can now power up the next Tool Board and commission it in the same way, choosing a different CAN address for it.

The Toolboard supports probe type 8 (unfiltered switch) and 9 (BL Touch). To connect a BL Touch, see table below.

Toolboard IO_0 connector pin	BLTouch pin	Colour
io0_out	Control	Orange
GND	GND	Black + Brown
io0_in	OUT	White
5V_EXT	+5V	Red

RepRapFirmware 3.2 and later support filament monitors attached to tool and expansion boards. Connector IO1 provides a 3.3V supply and 3.3V input signal level, suitable for a Duet3D laser or Rotating Magnet filament monitor. Here's an example of connecting a Rotating magnet filament monitor to a tool board.

Note different versions of the Magnetic Filament Monitor had different pinouts, check the wiring diagram

From version 1.1 the Toolboard has a footprint to allow adding an Omron D2FD-1L30-1T ultra subminiature switch or similar. From v1.2 the footprints for an ITR20001/T or TCRT1000/1010 reflective optical sensor are also added. Note these overlap so only a mechanical switch or optical reflective sensor can be used, not both.

The switch has three through hole pins and is designed to be placed as shown, with the pins soldered on the other side of the board. Do not attempt this addition if you are not comfortable soldering a through hole component to a PCB with a soldering iron. In addition be careful not to excessively heat or stress the PCB while adding the switch.

For an overview of using accelerometers to capture data on axis movement see:

Accelerometers

See Configure Accelerometer for how to setup the accelerometer, including its orientation in relation to the printer XYZ axis.

Forum user "Nuramori" has produced a graphical guide to help illustrate the orientation options:

https://www.dropbox.com/s/hu2w5mk57l4zqp...

There is limited support for the integrated accelerometer in RRF v3.3, further support is planned for v3.4

Accelerometer data can be captured and written to a file. There is a plugin for RRF in 3.3RC1 that will display the data:

• Changed to a slightly shorted JST VH power input header - makes plugging and unplugging it easier on a Toolboard mounted on a Hermera.
• 2 more footprints for either an ITR20001/T or TCRT1000/1010 reflective optical sensor to be added to the board as an alternative to the IO3 microswitch. Note all these footprints overlap so only one can be fitted.
• There are now 2.54mm spaced through hole pads under all JST PH connectors. The connectors could be de-soldered and replaced with screw terminals (note doing this would void any warranty).
• SWD programming header removed due to lack of space. Pads are available under the PCB.
• Accelerometer moved to the edge of the board that would be at the bottom if the board was mounted on an e3d Hermera.
• The driver and IO0 connector have moved slightly (see the v1.2 dimension diagram above)

• Added a LSI3DH accelerometer.
• Changed all headers other than VIN, OUT0 and CAN to JST PH right angle connectors. Note the screw terminal holes are still on the PCB so the PH connectors could be desoldered (or not fitted) and screw terminals used instead.
• Added a footprint for a Omron D2FD-1L30-1T or similar switch, connected to IO3.in
• Added a solder jumper that brings a 120R CANFD bus terminating resistor into the bus circuit to allow a toolboard to be directly connected to a Duet 3 mainboard without a tool distribution board.
• Board dimensions changed slightly (mounting holes unchanged) see the Dimensions section above
• Added a jumper to switch VOUT on OUT1 and OUT2 between 12V and VIN.
• Rename DIAG LED to STATUS and LED1 to ACT on silk screen to match other Duet 3 boards
• Added Programming pads so the SWD header does not need to be used for initial programming.
• Various other changes to component location and routing to accommodate the above changes

• Recessed the VIN connector even more from the edge of the board, to improve ease of wiring.
• Changed OUT_0 terminal block to 3.5mm to make it easier to insert thicker heater wires
• Added IO_2 as an additional 3 pin IO header - an example use case is an endstop or tool pickup detect switch mounted on the tool.
• Changed Temp 1 to JST ZH to make space for IO_2
• Increased LED1's brightness
• The three pin terminal blocks used are slightly higher than the 0.6, this will be reverted to the normal height on the next production run.
• Added a pulldown resistor so that OUT0 defaults to off if no firmware is loaded

Changes from the prototype board listed below

• Removed TEMP2 input to make space for larger screw terminal headers
• Change power connector polarity and position/footprint to match other Duet 3s and make it easier to mount.
• 5V LED added
• Out0, Temp0, Out1, Out2,IO_0 and Temp 1 changed to screw terminals.
• Board outline changed to rectangular