ESP32-P4-EYE Pinout & GPIO Reference(Camera, LCD, I/O Header)

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The ESP32-P4-EYE is one of Espressif’s newest dev kits: a tiny “camera-in-a-box” based on the ESP32-P4 SoC, with a built-in LCD, 2 MP camera, microphone, MicroSD and dual USB-C ports. It’s designed as a ready-made platform for AI vision and audio projects.

Unlike the usual DevKitC boards, the P4-EYE hides most of the hardware inside a plastic enclosure, but it still exposes a 2×10 female header so you can add your own sensors and actuators.

This guide gives you a practical overview of:

• What’s on the board
• How power & USB work
• How the 2×10 header fits into the picture
• Which pins are “safe” to use and which ones are tied to on-board peripherals

⚠️ Important: Espressif don’t provide a text pin table for the 2×10 header in the user guide – only a schematic/PCB PDF. For exact per-pin mapping, always cross-check your board revision against the official schematic in the docs.

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1. Board overview

On the front/top PCB you have:

• 1.54″ SPI LCD (240×240, ST7789 controller – backlight on LCD_BL = GPIO20)
• MIPI-CSI camera (2 MP, OV2710 sensor)
• MicroSD slot (4-line SDIO / SDIO 3.0, can also be used via SPI)
• Two USB-C ports
  • USB 2.0 – High-Speed USB device (connected to ESP32-P4 HS OTG)
  • Debug – Full-Speed USB-Serial/JTAG + power
• User buttons (3× side buttons, free for your own UI)
• Power switch and charge indicator LED

On the back PCB you have:

• ESP32-P4 SoC (dual-core RISC-V, with 16 MB SPI flash + up to 32 MB PSRAM)
• ESP32-C6-MINI-1U module for Wi-Fi 6 / BLE / 802.15.4 radio offload
• Digital microphone (PDM)
• Fill light LED
• Rotary encoder (for menu navigation / zoom, etc.)
• MIPI-CSI connector for the camera ribbon
• The 2×10 female header for extra GPIO

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2. Power options

From the official user guide:

You can power ESP32-P4-EYE in three ways:

1. USB 2.0 Device port (HS)
   • USB-C, marked USB 2.0 on the case
   • Powers the board and gives you a High-Speed USB device interface
   • Typical for mass-storage / UVC / custom USB experiments
2. USB Debug port (FS)
   • USB-C, marked Debug
   • Recommended for firmware flashing and serial debugging
   • Provides power + USB-Serial-JTAG
3. Battery connector (inside the case)
   • Small JST-style connector on the PCB
   • 1-cell Li-ion/LiPo pack (≤ 4 mm × 25 mm × 45 mm)
   • Battery is charged automatically when USB is plugged in

For most dev work, you’ll simply: plug a USB-C cable into the Debug port and flash from ESP-IDF.

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3. The 2×10 female header

ESP32-P4-EYE exposes a 2×10 female header (20 pins total) on the PCB back. The user guide describes it simply as a:

“2 × 10P header, customizable based on application.”

Internally, this header carries:

• 3V3 / 5V power and GND
• Several ESP32-P4 GPIOs with full functionality (ADC, PWM, I²C, SPI, etc.)
• Some signals associated with MIPI-CSI and other high-speed blocks (not recommended for random reuse)

Because there is no official text table of the header pins, you should always:

1. Download the ESP32-P4-EYE schematic (linked in the docs as ESP32-P4-EYE Schematic.pdf)
2. Locate the female header symbol (usually J1/J2 or “Female Header”)
3. Identify which ESP32-P4 pins are routed there

For your blog article, you can embed a “Pinout overview” image from the schematic, and then a manual table created from it.

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4. On-board peripherals & reserved pins

Even without the exact header map, we know which ESP32-P4 pins are dedicated to on-board peripherals from the user guide + datasheets:

You should not reuse these pins unless you really know what you’re doing:

• LCD (SPI + backlight)
  • ST7789 display
  • Backlight control: LCD_BL = GPIO20 (documented)
  • Other LCD SPI pins (SCK, MOSI, DC, CS, RST) are also dedicated – see schematic
• Camera (MIPI-CSI)
  • Uses a MIPI CSI lane pair + control lines (CLK, HS/LP lanes)
  • These pins are high-speed and not for general I/O
• MicroSD slot
  • 4-bit SDIO: CMD, CLK, D0–D3
  • May be shared with SPI in some configurations
• USB 2.0 HS device
  • Uses a dedicated USB PHY interface (not re-routable as GPIO)
• Microphone (DMIC)
  • Uses PDM clock/data pins from the ESP32-P4
• Rotary encoder & buttons
  • Connected to GPIOs used in the factory firmware for UI
• ESP32-C6-MINI-1U
  • Is connected to the ESP32-P4 via SDIO/UART (for Wi-Fi/BLE), plus its own antenna, etc.

When building your own pinout table for your site, mark these pins as “reserved by board hardware”, even if they also appear on the header.

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5. “Safe” GPIO usage strategy

Because ESP32-P4-EYE is so packed, the safest approach is:

1. Scan the header pins in the schematic and mark:
   • Power pins: 3V3, 5V, GND
   • Pure GPIO signals not labelled with LCD, CAM, SD, USB, MIC, ENC, etc.
2. Treat those pure GPIOs as general-purpose “safe” pins for:
   • Digital I/O
   • PWM (LEDs, small servos)
   • I²C / SPI / UART (as long as they are not already assigned)
3. Avoid reusing any GPIO with labels like LCD_*, CAM_*, SD_*, USB_*, PDM_*, ENC_*.

You can still create a useful, semi-generic table like:

Category	Recommendation on ESP32-P4-EYE
Power	Use 3V3 from header for sensors; 5V only for modules that need it.
Ground	Several GND pins on the header – use any close to your signal.
Digital I/O	Use GPIOs not tagged as LCD, CAM, SD, USB, MIC, ENC in the schematic.
I²C	Pick any two free GPIOs as SDA/SCL and configure with gpio_num in code.
SPI	Same: choose free GPIOs for SCK, MOSI, MISO, CS.
UART	Any free GPIO can be mapped to TX/RX using the IO-mux in ESP-IDF.
PWM	Most free GPIOs support LEDC PWM timers.
ADC	Use GPIOs that are part of ESP32-P4 analog-capable set and not used by board peripherals (from SoC datasheet + schematic).

So your article can explain how to pick safe pins rather than pretending there is an official “GPIO4 is always free” style mapping (which would be misleading on this board).

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6. Example: controlling the LCD backlight (GPIO20)

One pin we do know by name from the user guide is the LCD backlight:

“ESP32-P4-EYE features the ST7789 display, which uses the LCD_BL pin (GPIO20) to control the backlight.”

Minimal ESP-IDF snippet (C) to fade the backlight with PWM:

#include "driver/ledc.h"
#include "esp_log.h"

#define LCD_BL_GPIO 20

void lcd_backlight_init(void)
{
    // Configure LEDC for PWM on GPIO20
    ledc_timer_config_t timer = {
        .speed_mode       = LEDC_LOW_SPEED_MODE,
        .timer_num        = LEDC_TIMER_0,
        .duty_resolution  = LEDC_TIMER_10_BIT, // 0–1023
        .freq_hz          = 5000,
        .clk_cfg          = LEDC_AUTO_CLK
    };
    ledc_timer_config(&timer);

    ledc_channel_config_t ch = {
        .gpio_num       = LCD_BL_GPIO,
        .speed_mode     = LEDC_LOW_SPEED_MODE,
        .channel        = LEDC_CHANNEL_0,
        .timer_sel      = LEDC_TIMER_0,
        .duty           = 0,
        .hpoint         = 0
    };
    ledc_channel_config(&ch);
}

void lcd_backlight_set_percent(uint8_t percent)
{
    if (percent > 100) percent = 100;
    uint32_t duty = (1023 * percent) / 100;
    ledc_set_duty(LEDC_LOW_SPEED_MODE, LEDC_CHANNEL_0, duty);
    ledc_update_duty(LEDC_LOW_SPEED_MODE, LEDC_CHANNEL_0);
}

Use it like:

lcd_backlight_init();
lcd_backlight_set_percent(100); // full brightness

That’s a nice “Hello peripheral” demo for your article.

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7. Getting started with software

For the Software section of your blog post, you can essentially mirror Espressif’s instructions:

1. Install ESP-IDF (v5.5 or newer) using the official installer or idf.py setup.
2. Clone the esp-dev-kits repo and check out the release/v5.5 branch examples for esp32-p4-eye.
3. Build and flash the factory example: idf.py set-target esp32p4 idf.py menuconfig # optional board-specific settings idf.py flash monitor
4. The stock demo gives you:
   • Camera preview
   • Photo capture / timer capture
   • Video recording to SD card
   • On-screen settings (resolution, saturation, contrast, etc.)

This is a good point in the article to show screenshots / photos of the UI.

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8. How to present this on your blog (esp32.co.uk)

For a polished SEO-friendly article, I’d structure it like:

1. H1: ESP32-P4-EYE Pinout & GPIO Guide (Camera Dev Kit with LCD & MicroSD)
2. Short intro paragraph explaining what P4-EYE is and where it fits in vs DevKitC.
3. Board overview section with labelled photos (front/back).
4. Power & USB section.
5. On-board peripherals & reserved pins (LCD, camera, SD, mic, encoder, C6 module).
6. Female header GPIO – explain how to use schematic to find safe pins; maybe embed a hand-drawn pin table based on your own reading of the PDF.
7. One or two example snippets:
   • Backlight (GPIO20) PWM control
   • Simple GPIO output on one header pin (e.g. LED or relay) once you’ve confirmed its number from the schematic.
8. Links & resources:
   • Official user guide
   • Schematic / PCB layout
   • ESP-IDF “Get Started”