Wiring

All connections to UPAN Core are pluggable terminal blocks in two rows along the long edges of the board, plus USB-C, the antenna socket, a Qwiic socket, the UPAN Axis socket and the light-pipe button. This page lists every terminal with its pin order and gives short wiring examples. Pin numbers count from pin 1 as marked on the board. The board is v2 and the firmware is in development, so treat values marked "not final" as such.

Warning: Wire everything with the power supply switched off at the mains side. Never plug or unplug a motor or a driver module while the supply is on — it destroys the driver. See Safety.

The terminals at a glance

Both variants have the same board and the same terminals. UPC2-T2 comes with two TMC2209 drivers in the sockets; on UPC2-T0 the sockets are empty. The labels are the ones printed on the board; the case lettering is not final yet.

Power

2-pin terminal PWR 12–24V, 5.08 mm.

The input has a 5 A slow-blow fuse, reverse-polarity protection and a 36 V TVS diode. 48 V is not supported. Supply choice and grounding are on the Power page.

Drivers in the sockets

Two StepStick sockets, one per axis. Supported modules: TMC2209 and TMC2226 in UART mode. The controller sets the motor current and microstepping over UART; there is no potentiometer to turn.

• The sockets are keyed: a module turned the wrong way does not fit. Check that VM and GND of the module match the marking on the board.
• StepStick modules from different makers differ in a few pins. Solder jumpers next to each socket set the pinout. From the factory they match the supplied drivers (BTT TMC2209 V1.2 layout). The procedure for other makers is not final yet.
• Each driver needs its heatsink. Keep the vents over the sockets free.
• Above about 28 V supply the sockets are switched off; see Power.

Motor 1 and motor 2

4-pin terminals, 5.08 mm, one bipolar stepper motor (4 wires) each, driven by the driver in the matching socket.

• Find the two coils with a multimeter: the two wires of one coil show a few ohms between them.
• If the motor turns the wrong way, do not rewire. Set the direction in the axis settings.
• A TMC2209 drives up to about 2 A RMS per motor with its heatsink. For a bigger motor, use an external driver on AXIS EXT.
• Two motors that must move as one (the two Y motors of a gantry): one on the socket, the other on an external driver on the AXIS EXT terminal of the same channel.

External driver, axis 1 and 2

8-pin terminals AXIS 1 EXT and AXIS 2 EXT, 3.81 mm. Each carries the same steps as the matching socket, as 5 V differential signals (RS-422 line driver). Use them for a stepper or servo driver with Step/Dir inputs.

• EN is a disable signal. The device drives it high whenever the e-stop is active or the motion core has not enabled the drivers.
• The socket and AXIS EXT of one channel get the same steps. Normally use one of them and leave the socket empty; use both only for two motors that move as one.

Example: differential inputs (typical stepper driver)

For a driver with opto inputs PUL+ PUL− DIR+ DIR− ENA+ ENA− (DM542 type):

Example: common-anode inputs

With a common anode, EN would work the wrong way round. Leave the driver's ENA input open.

Example: common-cathode inputs

Warning: When UPAN Core has no power, EN is low. Most DM542-type drivers are then enabled. Do not rely on EN alone to keep an external drive off.

Fast inputs and sensor supply

8-pin terminal FAST IN, 3.81 mm. Four fast inputs for limit switches, homing, a probe or a pulse counter, and the supply pins for sensors.

All inputs on UPAN Core are opto-isolated and take 5–36 V. A filter of about 0.5 ms suppresses contact bounce; the fast inputs count pulses up to about 1 kHz.

• Dry contacts and PNP sensors: connect them between +V (or +5V) and the input. COM1 is joined to GND on the board from the factory.
• NPN sensors: cut the solder jumper COM1-GND on the board and connect COM1 to the sensor supply (+V). The procedure is not final yet.

Warning: +V is the supply voltage itself. A sensor rated 10–30 V is fine at 24 V; check its rating before you use a higher supply.

Example: NC limit switches

Use normally closed (NC) contacts: a closed contact means "normal", a pressed switch or a broken wire means "triggered", so a cut cable stops the axis instead of being ignored. Which input is which limit is part of the axis settings in your package.

Example: 3-wire PNP sensor

Universal inputs

8-pin terminal IN, 3.81 mm. Six inputs for buttons, pedals, sensors and switches.

They work like the fast inputs, NPN or PNP, with their own common and jumper COM2-GND. Take the sensor supply from +V or +5V on FAST IN. These inputs are read a little more slowly; use the fast inputs for limits and probes.

Example: foot pedal on IN1

Outputs and e-stop

8-pin terminal OUT / E-STOP, 3.81 mm.

Outputs: connect a load (relay coil, valve, lamp, camera trigger through an optocoupler) between VM and OUTn. The output switches the load to ground, up to 0.5 A, with short-circuit and over-temperature protection. The load runs at the supply voltage: at a 24 V supply, use 24 V loads. The outputs clamp the voltage spike of a coil themselves.

E-stop: connect an NC stop button between pin 7 +5V and pin 6 ESTOP. A pressed button or a broken wire disables all drivers in hardware — the sockets, the external driver terminals and an UPAN Axis — and the firmware stops the program. Without a button, fit a wire jumper between pins 6 and 7, otherwise the drivers stay off.

This is a functional stop, not a safety-rated emergency stop. See Safety.

Example: 24 V valve on OUT1

PWM / servo and analog inputs

6-pin terminal PWM / AIN, 3.81 mm.

• An RC servo draws more current than the +5V pins give. Power servos from their own 5–6 V supply and join its minus to GND.
• A potentiometer of 1–10 kΩ: ends to +5V and GND, wiper to AIN.

RS485

3-pin terminal RS485 A B GND, 3.81 mm, for Modbus: a spindle inverter, industrial sensors, and MKS SERVO42D/57D motors as axes 5 and up (independent axes, not coordinated with axes 1–4).

• Connect A to A, B to B and GND to the ground of every device, with a twisted pair.
• If UPAN Core is at one end of the bus, fit the supplied jumper on TERM 120R.

Qwiic

A JST SH 4-pin socket (Qwiic / STEMMA QT, 3.3 V, 200 mA resettable fuse) for ready-made I2C sensor boards: weight, temperature, distance (ToF), motion (IMU), pH. Daisy-chain several boards with Qwiic cables.

Display

4-pin terminal DISPLAY +5V TX RX GND for the UPAN Display touch panel (coming later). +5V has a 500 mA resettable fuse.

UPAN Axis socket

A 2 × 7 pin IDC socket for the ribbon cable to an UPAN Axis module next to the Core on the DIN rail. It carries the steps of axes 3 and 4, the shared disable line, the limit inputs of axes 3–4 and 3.3 V logic power. The Core makes the steps for all four axes, so they move together.

The ribbon cable carries no motor power. Wire the module to the power supply on its own wires. Plug and unplug the ribbon cable only with the power off.

USB-C

• On a PC the controller shows up as a serial port (for upan-cli and upan-mcp) and as a USB drive: drop a package file on it to install the package.
• USB powers the logic for setup on a desk. Drivers in the sockets cannot move a motor from USB alone.
• USB and the power supply can be connected at the same time.

Antenna

Screw the supplied antenna onto the SMA socket. In a metal cabinet, Wi-Fi does not get out: mount the antenna outside the cabinet with an SMA extension cable.

Button and status light

One button with an RGB light pipe on the front.

The firmware for the button and the light is in development; the behaviour above is the target, not final yet.