SPI
8 pages across tutorials, modules, pinouts and guides.
SD and microSD Card Readers for ESP32: SPI, 1-bit and 4-bit
Two 3.3 V card reader boards with the SD bus brought out in full. What the two NC pins really are, which of SPI, 1-bit and 4-bit to use, what each measured, and the wiring for all three.
SPI TFT LCD Display Boards, 0.96 to 3.5 inch
Six colour SPI display boards that are one circuit on six outlines: the same eight holes, the same 15-way ribbon socket, a backlight switched by a transistor, and a driver library that takes one constant per size. Which size to pick, how to wire it, and what is different about each.
32x8 LED Matrix with MAX7219, 3-Pack
Four 8x8 squares in one strip, 256 LEDs, three signal wires. What the pads are called, why the sketch has to say four, and what to do about a 3.3 V board on a chip that wants 3.5 V.
Logic Level Converters: MOSFET 2/4/6-Channel, TXB0108 and TXS0108
Five boards that let a 3.3 V board and a 5 V part share a wire safely. Which one to use for I²C, SPI, serial or an LED strip, which side is which, and the three wires that come before any signal.
Logic Analyzer Kit, 8-Channel 24 MHz
Eight channels sampled at up to 24 MS/s, straight up a USB cable. It decodes I²C, UART and SPI at the speeds a microcontroller actually runs, and the sample rate is the number that decides the rest.
1.8-inch TFT Display
A 1.77-inch colour TFT, 128 by 160 pixels, with an ST7735S controller on SPI, on a TinkerBlock board with an eight-pin header. 3.3 V only, with nothing on the board to shift 5 V signals down: an Uno goes through a TK97. The backlight stays off until BL is driven HIGH.
8x8 LED Matrix
Sixty-four red LEDs and a MAX7219 that scans them for you, on the TinkerBlock TK52: five wires, VCC on 5 V, a picture sent as eight bytes. The page is shared with the chainable 3-pack module, and only that one can be chained: the TK52 has no DOUT.
Logic Level Converter
Six bidirectional channels between 3.3 V and 5 V on a TinkerBlock board: L1 to L6 in a socket on the 3.3 V side, H1 to H6 on a header on the 5 V side, each a BSS138 with a 10 kΩ pull-up either side. It needs only 5V and GND: an ME6211 regulator makes the 3.3 V side's supply, so the socket's 3V3 pin is an output that powers a 3.3 V block, and is never fed.