serial

Serial Debugging

Use this skill for UART/COM-port observation and command exchange during embedded bring-up.

Capabilities

• Scan available serial ports.
• Monitor text output with filters and timestamps.
• Send text or hex payloads, optionally with CR/LF and response wait.
• View binary streams as hex dumps.
• Record logs to text, CSV, or JSON.
• Use a mux helper so monitor/log/send can share one hardware port when configured.

Configuration

Workspace-level config lives in .embeddedskills/config.json:

{
  "serial": {
    "port": "COM3",
    "baudrate": 115200,
    "bytesize": 8,
    "parity": "none",
    "stopbits": 1,
    "encoding": "utf-8",
    "timeout_sec": 1.0,
    "log_dir": ".embeddedskills/logs/serial"
  }
}

Parameter priority: CLI arguments > workspace config > .embeddedskills/state.json > defaults.

Commands

Scan:

python <skill_dir>\scripts\serial_scan.py --json

Monitor:

python <skill_dir>\scripts\serial_monitor.py `
  --port COM3 --baudrate 115200 --timestamp --timeout 10

Send text:

python <skill_dir>\scripts\serial_send.py `
  --port COM3 --baudrate 115200 "AT" --crlf --wait-response --json

Send hex:

python <skill_dir>\scripts\serial_send.py `
  --port COM3 --baudrate 115200 "01 03 00 00 00 02" --hex --json

Hex dump:

python <skill_dir>\scripts\serial_hex.py `
  --port COM3 --baudrate 115200 --timeout 10

Log:

python <skill_dir>\scripts\serial_log.py `
  --port COM3 --baudrate 115200 --duration 30 --timestamp --json

Rules

• Never send data unless the user asks or the task clearly requires it.
• Do not guess a port when multiple ports are present; ask or list candidates.
• Do not guess baud rate. Use project config, firmware constants, schematic notes, or the user's value.
• Prefer passive monitor/log before sending commands to an unknown device.
• For binary protocols, use hex or send --hex and record exact bytes.
• If a port is busy, report likely causes: another terminal, IDE monitor, flash tool, or mux state.
• When using mux, warn that multiple writers can corrupt the serial stream.

Bring-up Pattern

For MCU firmware debugging:

1. Scan ports and confirm the expected adapter.
2. Monitor for reset/banner output.
3. If no output, verify baud rate, TX/RX direction, voltage domain, firmware UART init, and whether the current HEX was flashed.
4. Log evidence before changing firmware.
5. For commands, send one minimal request and wait for response.