Which way round
The ESP32-S3 drops into any of the four bases just as easily end for end as the right way round, and the wrong way wires its 3.3 volt output to its own ground. The two boxes printed USB are the whole check.
Two boxes printed USB
Every one of the four bases has the same two black sockets, and at the bottom of each, between them, are two small outlines with USB printed in them. The pictures on this page are the PinPulse; the expansion, pluggable and screw bases draw the same boxes in the same place, and each has its own page about seating the board at the start of its chapter. The ESP32-S3's two USB sockets go over those boxes. Its antenna then sits at the other end, under the display port.
That is the whole instruction, and it is the one that matters most. What is worth a page is why: nothing on any of the four bases stops the other way.
It fits both ways
Both black sockets are 22 positions long and 22.86 mm apart, and the board's two rows of pins are too. Turn the board end for end and it seats just as firmly.
Turned round, the board's left row goes into the shield's right socket and runs the other way. So the board's two 3V3 pins land on the shield's bottom-right GND rows — and that ground row is also where two of the board's real ground pins have landed. The regulator's output is now wired straight to ground.
At the same time the board's 5V pin lands on the shield's GPIO 43 row, which goes into one of the inverter chips, whose own supply is now at zero.
What you will notice
Nothing lights. Not the shield's LEDs and not the red power LED on the ESP32-S3 itself, because the 3.3 volt rail it sits on is shorted. The regulator gets hot. Your computer may complain about the USB port.
So: seat the board first, then plug in the cable. If nothing lights, the cable comes out before anything else happens, and then you look at which end the USB sockets are.
The regulator on the ESP32-S3 has its own current limit and shuts itself down when it overheats, so a few seconds backwards is often survivable. It is still the one mistake on this board that can end a session.
When it does not work
Unplug the cable first, then look at the USB sockets. If they are at the display-port end rather than over the boxes printed USB, the board is in backwards and its 3.3 V output is shorted to ground. Take it out, turn it round, and try again before plugging anything else in.
Often not. The regulator on the ESP32-S3 limits its own current and shuts down when it gets too hot, which is what a short makes it do. Turn the board round and try it. If it now uploads and the LEDs work, carry on; if an LED column stays dark, the inverter chip for that group may be damaged.
A pin is folded under the board or missing its socket. Lift it out straight, check that all 44 pins are straight, and press down evenly with a thumb at each end. A half-seated pin works one moment and not the next.
The board is one socket position too far up or down, with a pair of pins hanging off the end. Both black sockets are exactly 22 long, so the board's ends should line up with the socket ends.
The one ribbon socket every base has, and the GPIO behind each of its fifteen contacts.
The display plug →Edit this page — content/books/esp32s3-base/which-way-round.mdx
Questions people ask first
Which way round does the ESP32-S3 go on the base?
Its USB sockets go over the two boxes printed USB, at the bottom of the base, with the antenna end at the top under the display connector.
Nothing stops the other way: the two sockets are identical, so the board seats just as firmly end for end. Put in backwards, its 3.3 V regulator output ends up wired to ground, and the board can be damaged for good. Seat the board first and plug the USB cable in second, every time.
Where does the power for my sensors come from?
The base has no regulator, no battery connector and no power input. It is powered through the ESP32-S3's own USB sockets, and every power way on it is one of that board's pins carried out.
The 3V3 ways are the output of the regulator on the ESP32-S3. The 5V ways are the board's 5V pin: about 4.6 V with a USB cable plugged in, and nothing without one. Nothing on the way is switched, fused or filtered.
Can I run a motor, relay or LED strip from the base?
Not from its power ways. Motors, relays, servos and long LED strips need their own supply, with its ground joined to a GND way on the base, because the ESP32-S3's regulator is small and is also running your sketch.
Small sensors and a display can take 3V3 and ground from the base. No current rating is quoted for the ways, because none has been checked.
How many GPIOs does the Pluggable Terminal Base bring out?
24 of the ESP32-S3 Gold's 36 GPIOs, once each, on two 12-way push-in blocks, plus two 4-way power blocks.
Twelve do not come out: 0, 1, 2, 3, 4, 35, 36, 37, 43, 44, 45 and 46, and the RST pin. GPIO 1, 2 and 4 reach the display connector and nothing else. All of the I²C and SPI pins are on the left block, and GPIO 19 and 20 (the native USB pair, on the right block) should be left alone while a sketch is using USB.
How many GPIOs does the Screw Terminal Base bring out?
26 of the ESP32-S3's GPIOs, once each, on two 15-way screw terminal blocks, with 3V3 on the left block and 5V on the right. Ten GPIOs do not come out.
The native USB pins (GPIO 19 and 20) are on the right block: a wire on either one shares the USB lines with the computer, so leave them alone unless the sketch is not using native USB.
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