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USB-C Pinout

24-pin receptacle, looking into the port, both rows shown. Check your board against its silkscreen before wiring power.

USB Implementers Forum
GNDA1TX1+A2TX1-A3VBUSA4CC1A5D+A6D-A7SBU1A8VBUSA9RX2-A10RX2+A11GNDA12GNDB12TX2+B11TX2-B10VBUSB9SBU2B8D-B7D+B6CC2B5VBUSB4RX1-B3RX1+B2GNDB1A rowB rowRotationally symmetric: B1 sits diagonally opposite A1, which is what makes the plug reversible
PowerGroundControlUARTSPI

Two rows, rotated not mirrored

The 24 pins sit in an A row and a B row with 180 degree rotational symmetry, so B1 lands diagonally opposite A1. Flip the plug and every signal still meets something valid, which is the whole reason the connector is reversible. The CC pins tell both ends which orientation happened.

What each signal does

VBUS carries power, 5 V by default and up to 20 V after a USB-PD negotiation. D+ and D- are the USB 2.0 pair that still runs most gadgets, duplicated on both rows in a receptacle. TX and RX pairs carry SuperSpeed traffic, and the SBU pins only wake up in alternate modes such as DisplayPort.

The 5.1 k resistors

A device signals "I am a sink, please send power" with 5.1 kΩ pull-downs on CC1 and CC2. Without them a proper charger sends nothing at all, which is the single most common reason a home-made USB-C board stays dark. In a full-featured plug, B5 becomes VCONN instead of a second CC.

Sources and datasheets

This diagram was cross-checked against the manufacturer documentation below plus at least two independent references before publishing. When they disagreed, the manufacturer won.

More boards and plugs live on the pinouts index.