embedded-serial-log-debug

# Embedded Serial Log Debug ## Overview Use this skill to make serial logs trustworthy before drawing conclusions from them. Confirm wiring, voltage level, port ownership, baud settings, boot timing, and log source before debugging firmware behavior. ## When To Use Use this skill when: - The user needs UART boot logs, serial console access, or firmware printf output. - Serial output is missing, garbled, intermittent, delayed, duplicated, or stops mid-boot. - The task involves USB-to-UART adapters, `screen`, `picocom`, `minicom`, logic analyzers, boot logs, or console prompts. Do not use this skill when the problem is already proven to be a higher-level protocol issue unrelated to raw serial capture. ## First Questions Ask for: - Board/chip and which UART pins are used. - USB-to-UART adapter model and voltage level. - Serial device path, such as `/dev/ttyUSB0` or `/dev/ttyACM0`. - Baud rate, data bits, parity, stop bits, and flow control if known. - Whether logs are expected from boot ROM, bootloader, kernel, RTOS, or application. - Whether TX/RX/GND are accessible and common ground is connected. ## Workflow 1. Confirm electrical compatibility. Check voltage level, common ground, TX/RX crossing, and whether pins are shared with boot/download modes. 1. Confirm terminal ownership. Ensure no other terminal, programmer, modem manager, or IDE owns the serial port. 1. Start with common settings. Use 115200 8N1 no flow control unless the board documentation says...