Pinout

Pinout refers to the mapping that identifies the function associated with each pin in a connector, socket, or integrated circuit package. It specifies which pin is ground, which supplies power, and which carries data, control, or timing signals. Pinouts are essential for wiring, troubleshooting, and cross-compatibility, and they vary between devices, standards, and revisions. To interpret a pinout, engineers consult the device’s datasheet or a pinout diagram that shows pin numbers, signal names, voltage levels, and sometimes allowable currents.

Common pinout conventions vary by connector type. For through-hole and surface-mount headers on printed circuit boards, pinouts are often shown in a diagram with a pin1 marker. Some headers are single-row; others are two-row with standard numbering schemes. In many families, pins in the same function (power, ground, I/O) appear in predictable positions, but this is not universal. In USB, for instance, a Type-A receptacle has four pins: VBUS (5V), D−, D+, GND; connectors from different vendors may differ in mechanical keying but preserve the same electrical functions. For microcontroller boards, pinouts map the 40- or 20-pin headers to GPIO, power, and peripheral signals.

Usage tips: always verify pinout against the official datasheet, confirm pin1 orientation, and avoid applying power to incorrect pins. When in doubt, test continuity with a multimeter and use labeled breakout boards to prevent miswiring.