No ports detected

The Port list in the Board Config panel reads No ports detected when Windows is not offering LadderIDE a serial port. The list is filled from the serial ports the operating system reports, so an empty list means the operating system has none to give — not that LadderIDE failed to look. No ports detected is a label rather than a port: it is never sent to the board and never saved into the project.

LadderIDE re-reads the list by itself after every successful upload, which is when a port most often appears or changes. Click ⟳ Refresh Ports to read it again at any other time — after plugging a board in, or after installing a driver.

A board can be plugged in, powered, and visible in Device Manager and still produce no port. Which of the causes below applies depends on the board.

Teensy 4.x and Raspberry Pi Pico: the port appears only after the first upload

On an Uno, a Nano, or a Mega, the serial port belongs to a separate USB chip on the board, so the port exists whenever the board is plugged in. A Teensy has no such chip. Its USB behaviour is compiled into the sketch, which means a Teensy offers a serial port only while it is running a sketch that was built to provide one.

A Teensy therefore shows no port when it is:

brand new, with no sketch programmed yet;
sitting in its bootloader, after the program button was pressed;
running a sketch built with a USB type other than Serial — Raw HID, MIDI, Keyboard, or Flight Sim, which a sketch from another development environment may well have used.

LadderIDE always builds for USB type Serial, so the first upload from LadderIDE puts a serial port on the board. Uploading does not need a port, because the Teensy Loader reaches the board over USB HID rather than over a COM port.

A Raspberry Pi Pico or Pico 2 behaves the same way for the same reason: its serial port also comes from the sketch, a board held in BOOTSEL appears as a drive rather than a port, and its upload tool finds that drive on its own. The steps below apply to both families — pick your board, upload with no port, and let the port appear afterwards.

Get the board online

Open the Board Config panel and set Board to your board — Teensy 4.0 or Teensy 4.1, or one of the Raspberry Pi Pico entries.
Leave Port showing No ports detected. The port field is not used when uploading to either family.
Press Ctrl+U to upload, or Ctrl+Shift+U to compile and upload.
The Output pane prints Uploading… (this board is programmed over USB, no port needed). No port is passed to the upload, because the Teensy Loader does not use one.
Wait a few seconds after the upload finishes. The Teensy restarts into the new sketch, Windows enumerates the serial port it now provides, and LadderIDE picks it up on its own — the Port box stops reading No ports detected and shows the port. If it does not, click ⟳ Refresh Ports.
Press Ctrl+K (Arduino ▸ Get Online). The rungs and the Tag Browser show live values.

From then on the port is there whenever the board is plugged in, because the sketch on the board provides it. Reprogramming the Teensy from another development environment with a non-Serial USB type removes the port again.

If the upload does not start

The Teensy Loader restarts the board into its bootloader over USB. A board running a Raw HID or MIDI sketch usually still accepts that restart, but if the upload sits waiting, press the program button on the Teensy and upload again. While the board is in its bootloader it shows no port, which is normal; the port appears after the new sketch starts.

Confirm what the board is running

To see which USB identity a Teensy is presenting, open Device Manager, enable View ▸ Devices by connection or find the device under Human Interface Devices, open its Properties ▸ Details page, and read Bus reported device description:

Reported description	What it means	Port?
`USB Serial`	Running a sketch built with USB type Serial	Yes
`Teensyduino RawHID`	Running a sketch built with USB type Raw HID	No
`Teensyduino MIDI`, `Teensyduino Keyboard`	Running a sketch built with that USB type	No
`HalfKay Bootloader`	Waiting in the bootloader for an upload	No

Other boards

Symptom	Likely cause	Fix
A clone Uno, Nano, or Mega shows a warning triangle in Device Manager	The board uses a CH340 USB-serial chip and Windows has no driver for it	Install the CH340 driver from the chip vendor, then unplug and replug the board
No new device appears in Device Manager at all when the board is plugged in	The USB cable carries power only, or the cable or port is faulty	Use a cable known to carry data; try a different USB port, preferably one directly on the computer rather than through a hub
The port was listed a moment ago and is now gone	Another program holds the port, or the board reset while the port was open	Close the other program, or its serial monitor, and click ⟳ Refresh Ports
Get Online says `Set the serial port in Board Config`	No port is chosen, because none is on offer	Work through the causes in this table; the message means the Port box holds the placeholder, not a port
The board is listed but Get Online shows no values	The sketch on the board is not the one LadderIDE built, or the tags are not referenced by any rung	Upload again from LadderIDE; a tag is broadcast only when a rung references it
A Raspberry Pi Pico or Pico 2 shows no port	The board is in BOOTSEL mode and appears as a drive, or is running a sketch that does not provide a serial port	Upload the sketch with Port left on `No ports detected`, the same way as a Teensy above; the port appears when the board restarts into it

Boards outside the AVR family — Teensy, STM32 Nucleo, Raspberry Pi Pico, ESP32 — also need their board support downloaded once. LadderIDE offers that download on the first compile for the board, and the download has no bearing on whether a port is listed.