Cheap Yellow Display (CYD)
The CYD (ESP32-2432S028R board) is an ESP32 module with a 2.8" color TFT display and built-in touchscreen, popular for being cheap and complete for interface projects.
It is easily found on marketplaces such as AliExpress and Shopee at very low prices for the hardware you get.
Schematic diagram
Power supply, CH340C USB-to-serial converter, AMS1117 regulators, LDR divider, RGB LED, micro-SD card and flash:
ESP32-WROOM-32, the 18-pin LCD connector, the XPT2046 touch controller and the audio amplifier:
Pinout
Board dimensions (78 × 42 mm PCB, mounting holes 4 mm in from the edges):
Specifications
| Category | Details |
|---|---|
| MCU | ESP32-WROOM-32 (dual-core Xtensa LX6 @ 240 MHz, Wi-Fi b/g/n + BT v4.2) |
| Flash / RAM | 4 MB QSPI flash, 520 kB SRAM |
| Display | 2.8" TFT 240 × 320 (ILI9341), 65 k colours, back-light on GPIO 21 |
| Touch | Resistive, XPT2046 controller on VSPI bus |
| Audio | PAM8002A 3 W class-D amp, GPIO 26 |
| Storage | micro-SD (up to 32 GB) on VSPI |
| On-board I/O | RGB LED (GPIO 4/16/17, active-LOW), LDR (GPIO 34) |
| User buttons | BOOT (GPIO 0), RESET (EN pin) |
| Free GPIOs | 35 (input only), 22, 27 on JST headers |
| Power input | 5 V via micro-USB, dual AMS1117 LDOs @ 3.3 V |
| Typical draw | ≈ 115 mA with back-light full-bright |
| Size / Weight | 86 × 50 mm, ~50 g |
Functional map
| Block | Interface | ESP32 pins | Notes |
|---|---|---|---|
| LCD (HSPI) | SPI | 12 (MISO), 13 (MOSI), 14 (SCK), 15 (CS), 2 (DC) | RST tied HIGH |
| Touch (VSPI) | SPI | 39 (MISO), 32 (MOSI), 25 (SCK), 33 (CS), 36 (IRQ) | |
| micro-SD (VSPI) | SPI | 19 (MISO), 23 (MOSI), 18 (SCK), 5 (CS) | Shared VSPI |
| Audio out | DAC/PWM | 26 | 2-pin JST |
| RGB LED | GPIO | 4 (R), 16 (G), 17 (B) | active-LOW |
| LDR | ADC | 34 | 10-bit ADC1 |
| Exposed headers | JST-P1 (UART), P3, CN1 |
Pinout at a glance
| Header | Pinout | Typical use |
|---|---|---|
| P1 (UART) | VIN – TX (1) – RX (3) – GND | Firmware flashing / serial console |
| P3 | GND – 35 (IN) – 22 – 21 (BL) | Extra GPIOs; avoid 21 if back-light needed |
| CN1 | GND – 22 – 27 – 3V3 | Ideal I²C header (22=SCL, 27=SDA) |
| P4 | 26 – GND | Speaker |
| Buttons | BOOT (0), RESET (EN) | Flash & reset control |