The display plug
The fifteen-way ribbon socket at the top is the one display plug every Lonely Binary screen shares. Contacts 1 to 9 are named and in a fixed order, so a display goes in with no wiring, and the library's pin numbers are already the ones on this board.
One plug for every screen
At the top of the shield, above the six chips, is a white socket fifteen contacts wide at a 1.0 mm pitch. It is Lonely Binary's standard display plug. The same fifteen-way ribbon, in the same order, goes into every panel of the SPI TFT display kit, from the 0.96 inch strip to the 3.5 inch screen, and the arcade mainboard has the same socket with the same nine contacts.
So a display is one cable, and there are no pin numbers to look up. The shield wires contacts 3 to 9 to the pins the display library already uses on an ESP32-S3: GPIO 12 is the clock, 11 the data, 2 data-or-command, 42 reset, 10 chip select and 41 the backlight. Plug a ribbon in, select the ESP32-S3 board, and the library's defaults reach the screen.
Contact by contact
Contact 1 is ground and contact 2 is 3.3 volts, from the same rail as the edge rows. Contacts 3 to 9 are the display's signals, always in this order:
| Contact | Signal | GPIO | What it does |
|---|---|---|---|
| 3 | BL | 41 | the lamp behind the glass |
| 4 | RST | 42 | a clean start for the controller |
| 5 | DC | 2 | says whether the byte is a command or a pixel |
| 6 | MISO | 13 | data back from the display |
| 7 | SCK | 12 | the SPI clock |
| 8 | MOSI | 11 | the pixels and commands |
| 9 | CS | 10 | this display is the one being addressed |
A panel in the display kit uses eight contacts: ground, 3.3 V and every row above except MISO, because nothing is read back from it. Contacts 10 to 15 are GPIO 1, 15, 7, 4, 6 and 5, named D2 to D7 in the board's design files; they are brought out for a screen that has more lines, and a TFT panel leaves them alone.
Every one of these GPIOs also comes out at the edge with its LED. The ribbon adds no pins; it is a second way onto thirteen you already have, and the LED beside each one loads the display's lines no more than it loads any other.
Getting the ribbon in
Open the latch, slide the ribbon in square until it stops, close the latch. Neither movement takes force: if you are pushing, the latch is still closed. The bare contacts on the ribbon face the socket's contacts. A ribbon the wrong way up is the same as no ribbon, and breaks nothing.
Use the cable that came with the display. Ribbons are made with the contacts on the same side at both ends or on opposite sides, and the other kind puts every contact on the wrong face. Take the shortest that reaches: the clock is fast and the cable is unshielded.
The two rows to ignore
The table on the back prints 20-1 and 22-15 where it should print 10-1 and 11-15. There is no contact 20 or 22 on a fifteen-way socket, and the board's wiring confirms it: contact 10 is GPIO 1, contact 11 is GPIO 15. The table's order is right. Only those two numbers are wrong.
What the plug does not cover
It is the plug for the displays that share it. The 1.8 inch TinkerBlock display (TK89) has eight header pins and no fifteen-way socket: its glass plugs into a smaller socket on the block itself. Wire it to the edge rows like any other module.
When it does not work
Check the ribbon first: fully inserted, square to the socket, latch closed, bare contacts facing the socket's contacts. A ribbon upside down connects nothing and damages nothing. Then check the controller: the panel's driver in your sketch has to match the chip behind the glass. Last, check you did not move the display lines in code: the defaults for this board are GPIO 12, 11, 2, 42, 10 and 41.
That is the display's colour order or inversion setting, one call in the driver. It is not a wiring fault: a wrong contact gives no picture or a white screen, not wrong colours.
A typing slip in the legend. A fifteen-way socket has no contact 20 or 22; those rows are contacts 10 and 11, wired to GPIO 1 and GPIO 15, in the order the table prints them. Every other row is right.
Only the ones the display leaves unused. The ribbon and the edge rows are the same wires, so anything you connect at the edge is also on the display's line. A TFT panel from the display kit needs eight contacts: GND, 3V3, BL, RST, DC, SCK, MOSI and CS. MISO and contacts 10 to 15 are free for something else.
Every GPIO on the ribbon has an LED at the edge, so the lines the display uses flicker while it draws. That is the display bus working. The LEDs load a line by one inverter input and do not affect the picture.
Edit this page — content/books/esp32s3-base/the-display-port.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.
Questions about this product
See what other owners have asked, and read their solutions.
This page covers several products. Choose yours to see the right discussions.
Discuss this article
Ask about this page. The answer stays here, on the page it belongs to, for whoever hits the same wall next.