What the shield does

A board for the board

The ESP32-S3 Gold Edition arrives with forty-four pins and nowhere convenient to put them. The shield is where they go: the board drops into two black 22-way sockets in the middle, and every one of its pins comes back out at the edges.

Six parts, one job each

Read from the outside in. The outer row on each edge is male pins, for the female end of a jumper wire. The yellow row beside it is female sockets, for the male end. Each socket is wired to the pin next to it, so the two rows are one set of signals offered twice.

Outside the pins is a column of LEDs, one beside every GPIO. Between the two black sockets, under where the board sits, are six inverter chips. They are what turns a pin's voltage into a lit LED without loading the pin, which is the subject of the next chapter.

At the top is a fifteen-way ribbon socket for a display, and at each corner a 4.7 mm mounting hole.

What the numbers mean

The number printed beside each row is the GPIO number — the one you type in pinMode() and digitalWrite(). The shield uses the same order as the ESP32-S3's own pins, so a GPIO sits at the same height on the shield as it does on the board.

The rows with no LED are the ones that are not GPIOs: 3V3, 5V, RST and GND.

When it earns its place

When you want to see a pin rather than measure it. A sketch that toggles GPIO 5 shows a light on row 5 with no LED, no resistor and no wire. A serial port flickers while it talks. A pin you forgot to configure glows when you put a finger near it. Everything else — the pins, the sockets, the display port — is what any base does.