ESP32 CYD ST7789 2.8-inches resistive touch display
Please note that there are no breadboard pins that expose GPIO pins, instead there are 3 JST 1.25 connectors available.This is an ESP32 Dev. Board with assembled ST7789 2.8-inches TFT display with SPI interface that has a resolution of 240 x 320 pixels and resistive touch surface (driver chip XPT2046). It is known as Cheap Yellow Display (“CYD”) and comes in several variants. Additionally, a Micro-SD-Card reader and a (true) RGB LED is on the backside of the device. There is an LDR Light sensor assembled on the front side, but a lot of people marked them as not working or useless (I did not verify this).
Variants of 2.8-inches CYD devices
- the first two versions are using a TFT display with driver chip ILI9341 and come with a Micro-USB connector (link to the description)
- the third version (this descriptions) is using the display with attached ST7789 driver chip. These devices do have a Micro-USB and a USB-C connector.
ESP32 CYD pin mapping overview
Documentation
This board is well documentated by the manufacturer and third party persons:
- Developer website: this specific device has the “device number” “ESP32–2432S028R”, that was developed by a Chinese company. Their website is difficult to find, here is a link to the folder (containing all models) and the specific product file. You will download a file of about 900 MB size!
- Probably the best website about the CYD is from a hobbyist, “witnessmenow” (Brian Lough), who maintains the GitHub repository “ESP32-Cheap-Yellow-Display” with a lot of FAQs and troubleshooting around CYD
- Another source for examples is “https://github.com/bitbank2/CYD_Projects”
- Sara and Rui Santos have a phantastic website around ESP32 topics, and they give a lot of information and examples, e.g. “Getting Started with ESP32 Cheap Yellow Display Board — CYD (ESP32–2432S028R)” and “ESP32 Cheap Yellow Display (CYD) Pinout (ESP32–2432S028R)”. Use their search for more tutorials on this device.
- Freenove ESP32 tutorial (19 different tutorials tested on ESP32 CYD)
- Hartmut Waller A lot of examples for the display, RGB LED and SD-Card reader [German]
- Modifications to the original CYD (audio e.t.c): (ESP32_TFT_PIO)[https://github.com/hexeguitar/ESP32_TFT_PIO]
Own tutorials
I wrote some tutorials regarding this device:
- Create a colorful digital clock on an ESP32 Cheap Yellow Display (“CYD”)
- Create an Internet Weather Station with 3 days Forecast on an ESP32 Cheap Yellow Display (“CYD”)
- How to use Touch and SD Card at the same time on an ESP32 Cheap Yellow Display (“CYD”)
- Play iconic Arcade Games like Pac-Man or Donkey Kong on ESP32 Cheap Yellow Display (“CYD”) [full guide]
- Create a digital clock in a Domino style on an ESP32 Cheap Yellow Display (“CYD”)
- Playing Othello / Reversi on an ESP32 Cheap Yellow Display with Minimax intelligence for the AI opponent
Libraries
The following libraries and version numbers are tested with this board:
- TFT_eSPI by Bodmer, version 2.5.43, https://github.com/Bodmer/TFT_eSPI
- LovyanGFX by Lovyan03, version 1.2.7, https://github.com/lovyan03/LovyanGFX
Development board profile
| Position | Characteristics |
|---|---|
| Processor: | ESP32 module with dual-core Xtensa LX7 (ESP32-D0WD-V3 (revision v3.1)), Flash 4 MB, no PSRAM |
| CPU Frequencies | 160/160/80 MHz (for WiFi), 40/20/10 MHz (no WiFi) |
| Pins available on Breadboard | 0, 4, 5, 12, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 32, 33, input only: 34, 35, 36, 39 (total 20), 3.3V, 5V, GND |
| Pins available on solder pads | NO |
| Pins available internally | 0 (BOOT button) and display (see below) |
| Pins for ST7789 | BL: 21, MISO: n/c, MOSI: 13, SCLK: 14, CS: 15, DC: 2, RST -1, HSPI-port, 80 MHz |
| Pins for XPT2046 Touch Controller | MISO: 39, MOSI: 32, SCLK: 25, SS/CS: 33, IRQ: 36 |
| Pins for Micro-SD-Card reader | MISO: 19, MOSI: 23, SCLK: 18, SS/CS: 5 |
| Pin for Light sensor | 34 |
| Pin for Speaker amplifier | 26 (no direct usage) |
| Pins safe to use | 22,27 and 35 (input only) on CN1 |
| Display | YES, ST7789 1.9-inches display, SPI interface, 170x320 pixels, no touch controller |
| Interfaces | 1x I2C, 2x SPI, 2x UART, 11x GPI0 (PWM), 4x ADC |
| Onboard Power LED | NO |
| Onboard GPIO LED | RGB LED, red: 4, green: 16, blue: 17 |
| USB-Connection | USB-C and Micro-USB, Controller: CH340 |
| Wi-Fi connector | PCB antenna |
| Wi-Fi | YES, 802.11 b/g/n (2.4 GHz), STA/AP/Mixed |
| Bluetooth Classic | YES, 5.0 |
| Bluetooth Low Energy (BLE) | YES, Bluetooth 5.0 LE protocols |
| Battery connector | NO |
| Battery loading | NO |
| Battery voltage measure | NO |
| Battery voltage measure control | NO |
| Extern voltage control | NO |
| Restart button | YES |
| BOOT button | YES, GPIO 0 |
| On-/Off Switch | NO |
| SD card reader | YES |
| Breadboard pins | NO pins but some 1.25 JST connectors |
| QWIIC connector | NO |
| Internal temperature sensor | YES |
| Low Dropout Voltage Regulator (LDO) | AMS1117 (1000 mA) |
| Breadboard pins distance (width) | 3,0 cm (does not fit on one breadboard) |
| Security features | Encryption hardware accelerators that support AES-128/256, hashing, RSA, HMAC, digital signatures, and secure startup |
| Expansion board | NO |
| Arduino board selection | ESP32 Dev Module |
ESP32 CYD back side pins
