Hardware and Pinout

🔬 Hardware & Pinout Reference

Technical overview of the SP-ESP32-S3-1.28-BOX hardware and GPIO mappings.

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📌 Complete GPIO Pinout Table

Warning

Board Revisions Notice: AliExpress vendors and clones occasionally update PCB revisions or route pins slightly differently (e.g., audio amplifier enable on GPIO46 vs GPIO48, or touch interrupt). Always verify your board's silkscreen markings if a peripheral does not initialize.

GPIO Pin	Function	Subsystem	Description
GPIO1	ADC1 Channel 0	Battery Monitor	2:1 resistor divider. Voltage: 3.3V (0%) - 4.2V (100%).
GPIO2	SPI MOSI	Display (GC9A01A)	Data transmission to round LCD.
GPIO4	SPI CLK	Display (GC9A01A)	SPI clock boosted to 80MHz.
GPIO5	SPI CS	Display (GC9A01A)	Chip Select (Active LOW).
GPIO6	Touch Reset	Touchscreen (CST816D)	Hardware reset line.
GPIO7	I2C SCL (Touch)	Touchscreen (CST816D)	Dedicated Touch I2C bus clock.
GPIO8	I2S DOUT	Audio Speaker	Serial audio data to internal amplifier / DAC.
GPIO9	I2S BCLK	Audio Codec (ES8311)	Bit clock for I2S audio stream.
GPIO11	I2C SDA (Touch)	Touchscreen (CST816D)	Dedicated Touch I2C bus data.
GPIO12	Touch INT	Touchscreen (CST816D)	Interrupt signal triggered by touch events.
GPIO14	I2C SCL (Audio)	Audio Codec (ES8311)	Codec control bus clock.
GPIO15	I2C SDA (Audio)	Audio Codec (ES8311)	Codec control bus data (Address: 0x18).
GPIO16	I2S MCLK	Audio Codec (ES8311)	Master clock output to the ES8311.
GPIO38	LCD Reset	Display (GC9A01A)	Display hardware reset line.
GPIO41	Digital Input	Charging Sensor	Logic HIGH when connected to USB-C 5V power.
GPIO42	LEDC PWM	Display Backlight	Active LOW (inverted: true). Frequency: 1000Hz.
GPIO45	I2S LRCLK	Audio Codec (ES8311)	Left/Right word select clock.
GPIO46	Digital Output	Audio Amplifier Power	Enables onboard speaker amplifier (Active HIGH).
GPIO47	LCD DC	Display (GC9A01A)	Data / Command control pin.

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⚡ Dynamic Audio Power Gating (GPIO46)

In standby mode, audio amplifiers consume ~20mA and produce an audible high-frequency hiss. SmartDisplay uses dynamic power management:

• Power amplifier (GPIO46) is set to ALWAYS_OFF in standby.
• When Home Assistant initiates a TTS voice stream, GPIO46 turns ON.
• 1000ms after the audio stream finishes, GPIO46 cuts power again.