Cardputer Adv Terminal

Terminal emulator for ESP32-S3 Cardputer Adv. It shows serial data on the built-in screen and sends keyboard input to USB CDC and/or UART.

Features

• USB CDC and UART serial input/output
• Line mode (send on Enter)
• Local echo toggle
• ANSI filter toggle
• CRLF toggle (default ON)
• Status bar with live settings and connection state
• Font size toggle
• Screen frame/margins for comfortable reading

Build and Upload (Arduino CLI)

Requirements:

• Arduino CLI installed
• ESP32 core installed with FQBN: esp32:esp32:m5stack_cardputer
• M5Cardputer library installed

Build:

make build

Upload:

make upload PORT=/dev/tty.usbmodemXXXX

Monitor (optional):

make monitor PORT=/dev/tty.usbmodemXXXX BAUD=115200

Cardputer Controls

• FN+1: Change PORT (USB -> UART -> BOTH)
• FN+2: Change BAUD
• FN+3: Toggle ECHO
• FN+4: Toggle ANSI filter
• FN+5: Clear screen
• FN+6: Toggle CRLF
• FN+7: Toggle font size

Notes:

• Line mode is default: typed text is sent only after Enter.
• Status bar highlights values when they differ from defaults.

Raspberry Pi Zero 2 W (USB host via OTG)

The Pi must act as USB host. Use the OTG port with an OTG adapter.

OTG host mode (config + commands)

Enable USB host mode for the OTG port:

1. Edit /boot/config.txt and add:

dtoverlay=dwc2,dr_mode=host

2. Reboot:

sudo reboot

3. Verify host mode is working (after reboot, with Cardputer plugged in):

lsusb
dmesg | tail -n 50

1. Connect Cardputer -> Pi Zero 2 W OTG port.
2. Verify device appears on the Pi:

dmesg | tail -n 50
ls /dev/ttyACM* /dev/ttyUSB*

You should see /dev/ttyACM0.

3. Start a getty on /dev/ttyACM0 so the login banner appears on the Cardputer:

sudo systemctl enable --now serial-getty@ttyACM0.service

4. Make it auto-start on every plug (udev rule):

Create /etc/udev/rules.d/99-ttyACM0-getty.rules with:

ACTION=="add", KERNEL=="ttyACM0", TAG+="systemd", ENV{SYSTEMD_WANTS}="serial-getty@ttyACM0.service"

Reload udev and reconnect:

sudo udevadm control --reload
sudo udevadm trigger

Now the Cardputer should show the Debian login banner whenever it is plugged into the Pi.

UART (TX/RX) Option

If you prefer GPIO UART, wire:

• Pi TX -> Cardputer RX
• Pi RX -> Cardputer TX
• GND -> GND

Set UART_RX_PIN and UART_TX_PIN in termputer/termputer.ino, then set PORT:UART or PORT:BOTH on the Cardputer.

Files

• termputer/termputer.ino - main sketch
• Makefile - Arduino CLI build/upload
• IMG_6746.jpeg - project photo