3.2 inch ESP32 CYD Display Module with resistive touch screen

The "Cheap Yellow Display" E32R32P (3.2 inch ESP32 CYD) combines a 3.2-inch IPS colour touchscreen with an ESP32-WROOM-32E development board. It provides a compact platform for building equipment interfaces, Wi-Fi dashboards, bench instruments and home automation panels. The resistive touchscreen responds to pressure from a fingertip or the included plastic stylus.

The ESP32 runs your application and controls the display, touch input, microSD card, RGB status LED and audio output. The onboard USB-to-serial interface lets you program and power the board over USB-C. Separate expansion connectors provide access to I2C, SPI, UART and two input-only GPIOs.

Display and processor specifications

• Board model E32R32P, also documented as Elecrow DHO27032B
• 3.2-inch IPS TFT LCD with 240x320 pixels and a 48.60x64.80 mm active display area
• ST7789P3 display controller with a 4-wire SPI interface
• RGB565 and RGB666 colour formats, with up to 262,144 colours in RGB666 mode
• White LED backlight with 300 cd/m² typical screen brightness
• Resistive touchscreen with an XPT2046 SPI touch controller
• ESP32-WROOM-32E module with an ESP32-D0WD-V3 processor, dual-core 32-bit Xtensa LX6 architecture and a clock speed of up to 240 MHz
• 4 MB QSPI flash, 520 KB SRAM and 16 KB RTC SRAM
• 2.4 GHz Wi-Fi (802.11 b/g/n), Bluetooth Classic (BR/EDR) and Bluetooth Low Energy (BLE)
• Approximately 93.7x55.0 mm board footprint with four mounting holes. Refer to the mechanical drawing for enclosure clearances.

Power, programming and onboard peripherals

• USB-C supplies 5 V and connects the onboard CH340C USB-to-UART bridge for firmware uploads and serial monitoring.
• The automatic download circuit normally handles bootloader entry. For manual entry, hold BOOT, press and release RESET, then release BOOT.
• The microSD slot operates in SPI mode and can store graphics, fonts, audio files and application data.
• The RGB LED has independently controlled red, green and blue channels. Each channel turns on when its GPIO is driven low.
• The onboard audio amplifier drives an external speaker connected to the 2-pin speaker header.
• The BAT connector accepts an optional single-cell 3.7 V lithium-polymer battery. The board includes a charging circuit and a battery-voltage sensing input. Match the battery lead polarity to the board markings.
• The manufacturer specifies approximately 160 mA at 5 V during display operation and approximately 510 mA with the display, speaker and battery charging active together. Typical battery charging current is approximately 290 mA.

External connector pin functions

• I2C, 4-pin, 1.25 mm pitch. SDA is GPIO32 and SCL is GPIO25. The connector also provides 3.3 V and GND.
• SPI, 4-pin, 1.25 mm pitch. SCK is GPIO18, MOSI is GPIO23, MISO is GPIO19 and peripheral CS is GPIO21. The clock and data lines are shared with the microSD slot, which has a separate chip-select line.
• UART, 4-pin, 1.25 mm pitch. TXD0 is GPIO1 and RXD0 is GPIO3, named from the ESP32’s perspective. These are 3.3 V logic signals and share UART0 with the onboard USB-to-UART bridge.
• Expansion inputs, 2-pin, 1.25 mm pitch. GPIO35 and GPIO39 are input-only and can be used for external signals.
• BAT, 2-pin, 1.25 mm pitch. Battery positive and negative connections for a single-cell lithium-polymer battery.
• SPEAKER, 2-pin, 1.25 mm pitch. The two amplified output terminals connect directly to an external speaker.

Onboard ESP32 GPIO assignments

• LCD and touch SPI bus. GPIO14 is SCK, GPIO13 is MOSI and GPIO12 is MISO.
• ST7789P3 display. GPIO15 is CS (active low), GPIO2 selects data or command (high for data, low for command), and GPIO27 controls the backlight (high turns it on). LCD reset is tied to ESP32 EN and is active low.
• XPT2046 touch controller. GPIO33 is touch CS (active low) and GPIO36 is touch IRQ (active low).
• microSD card. GPIO18 is SCK, GPIO23 is MOSI, GPIO19 is MISO and GPIO5 is card CS (active low).
• RGB status LED. GPIO22 is red, GPIO16 is green and GPIO17 is blue. All three channels are active low.
• Audio. GPIO26 provides the DAC signal to the amplifier. GPIO4 enables the amplifier when driven low.
• Battery monitoring. GPIO34 reads the battery voltage through an onboard 2:1 resistor divider.
• Buttons. BOOT pulls GPIO0 low. RESET pulls EN low and resets both the ESP32 and the display.

Use the E32R32P pin assignments when configuring your Arduino project. The LCD and touch controller share one SPI bus, while the microSD slot and external SPI connector share a second bus. Configure the chip-select pin for each device separately.