Three volts only
Every panel in the kit is a 3.3 volt part, and the boards say so in print on their own backs. An ESP32 or a Pico wires straight across; an Uno needs a level converter on every line, or it will eventually take the panel with it.
The rule is printed on the board
Turn a panel over and read the box in the bottom right corner. It says the board is for 3.3 volt microcontrollers such as an ESP32-S3 or a Raspberry Pi Pico, and that a 5 volt board such as an Uno R3 needs a logic level converter to avoid damaging the display.
That is not a disclaimer. It is the operating condition, and it is the single most expensive thing to get wrong in this kit.
What actually happens
A pin on a 5 V board, driven high, puts 5 V on a wire. The input it arrives at was built for a chip running from 3.3 V, and it has a protection diode from the pin to that 3.3 V supply. Above about 3.6 V that diode starts conducting, and current flows from your Uno, through the display's input, into the display's own supply rail.
Sometimes that survives. Sometimes it browns out the panel — the flicker the silkscreen warns about — and sometimes it kills the input. The failure that makes people give up is the slow one: a display that works for an afternoon and is dead the following week, with no single moment you can point at.
The two safe arrangements
A 3.3 V board. An ESP32, an ESP32-S3, a Pico, an STM32, an nRF52. Wire the eight pads straight across and there is nothing to think about. This is what the kit is designed for.
A 5 V board with a converter. Put a level converter between the two on every line heading towards the display — SCL, MOSI, DC, RST and CS — and run the panel's 3V3 pad from a 3.3 volt supply, not through the converter. A converter shifts signals; it does not make power.
Five signals is more channels than a two-channel board has, so this is the case for one of the eight-channel level shifters rather than a small MOSFET board. The converter handbook covers which is which.
And a thing worth checking either way
The backlight is the biggest load on any of these panels, and it switches on all at once. If your board browns out or resets at the moment the display lights up, that is not a logic level problem — it is a supply that has no headroom. Give the panel a rail that can carry it.
When it does not work
That is the normal way this goes wrong. Driving 5 V into an input specified for 3.3 V is not an instant failure — it is current flowing into a protection structure that was not designed to carry it, for as long as it lasts. It may run all afternoon and die next week, and the flickering that shows up first is the warning the board's own silkscreen mentions.
On the slow lines, at a push. Not on the clock, which is switching tens of millions of times a second into whatever capacitance the ribbon has, where a divider rounds the edges until the controller stops recognising them. Use a proper converter on all five signal lines and keep the wiring short.
No. The panel's supply pin is 3V3 and it goes to a 3.3 volt rail, always. A level converter shifts signals; it is not a regulator, and the low side of it needs the same 3.3 V the panel is running on.
A backlight is the largest single load on these panels, and a board whose 3.3 V regulator is already near its limit can brown out when it switches on. Power the panel from a supply with headroom rather than from a pin that is also running Wi-Fi.
Which GPIO each pad lands on, and why the panel has no say in it.
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