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`phpflash monitor`

Open the serial console on the board over the same USB cable you flashed with. It wraps idf.py monitor, so backtraces are decoded for you; the boot log shows the board coming up, mounting its card, and — on a networked board — the address it is reachable on.

phpflash monitor opens the serial console on the connected board, running idf.py monitor against the project's own build tree. It needs only a port and the tool paths — no manifest, no build args — so it starts fast. A project config, if present, supplies default path and port values, but monitor works without one.

bash terminal — monitor 
phpflash monitor            # autodetect the port
phpflash monitor -p /dev/ttyACM0

Flags

Flag Meaning
-p, --port <port> Serial port. Empty tries /dev/ttyACM*, then /dev/ttyUSB*, then lets ESP-IDF autodetect.
--idf-path <dir> ESP-IDF location (overrides config, env and default).
--php-esp32-path <dir> php-esp32 location.

The port is resolved just as it is for flash: the -p flag, then the config's [board].port, then the first serial device that exists (/dev/ttyACM* before /dev/ttyUSB*), else empty so ESP-IDF autodetects.

Leaving the monitor

The console runs until you exit it:

  1. 01

    `Ctrl-]`

    — leave the monitor and return to the shell.

  2. 02

    `Ctrl-T` `Ctrl-R`

    — reset the board without reflashing, so you can watch it boot again from the top.

Backtraces are decoded for you

Because monitor wraps idf.py monitor, a crash backtrace printed by the firmware is decoded to file-and-line against the build's ELF automatically — you do not run a separate address decoder. A board that keeps resetting with an out-of-memory backtrace usually means the app needs more PSRAM than the board has.

What the boot log shows

The serial output is where the firmware reports what it is doing. What appears depends on the board and the project, but the useful landmarks are:

text Serial console at boot (networked web-server board) 
microSD mounted at /sdcard
opcache: file cache at /sdcard/opcache
network up -- http://10.42.0.224/
web-server model: serving /app/index.php over HTTP on :80
  • microSD mounted at /sdcard confirms the card was found and mounted; a microsd project reads its source from there.
  • network up -- http://<ip>/ prints on a networked board the address it came up on. That is where you point a browser or curl for a web-server project.
  • An init-loop project's echo output — a linear script's lines, or the setup()/loop() ticks — streams here as it runs.

No serial port

If monitor finds nothing to open, check ls /dev/ttyACM* /dev/ttyUSB*. An absent port usually means the USB cable carries power only, not data. A busy port can be ModemManager probing the device on some distributions; add yourself to the dialout group, or free the port, and retry.

Last updated · 2026-09-04
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