UART, I²C and logic-analyzer evidence

What to understand

UART usually needs shared ground and verified voltage domains; TX/RX direction and the appropriate serial speed must be established before interpreting bytes.

I²C uses open-drain signals with pull-ups in a defined voltage domain. Seeing a static HIGH does not prove functioning transactions. Standard auto-direction level shifters can perform poorly for some waveforms.

A logic analyzer needs a suitable reference, sample rate and input-voltage tolerance. Debug interfaces are not proof of specific chip failures by themselves.

Safe practical workflow

1. Identify ground and measure idle signal voltage with a suitable meter before connecting the analyzer.
2. Using a low-voltage training board, record a short UART or I²C trace and note speed and sample rate.
3. Decode one known message or START/address/ACK sequence and save raw evidence.
4. List at least one possible decoding error such as incorrect baud, polarity, sample rate or noise.

हिंदी में मुख्य बात

UART/I²C या logic analyzer जोड़ने से पहले voltage level और common ground verify करें। गलत level से phone की signal line खराब हो सकती है।

Your practical assignment

Submit an annotated protocol capture or sample trace with voltage domain and confidence noted.

Use the AIFlasher bench worksheet for measured values, observations, unknowns and next tests. A simulated case is acceptable if you do not have the instrument yet.