OV7670 Module refers to the low-cost digital output CMOS camera from Micro-Snow Electronics.
Its camera includes a 300,000 pixel CMOS image sensor, 3.6mm focal length lens and lens mount, and various power supplies required for on-board CMOS chips.
The board also pulls out the control pins and data pins for easy operation and use.

3V3: Input power supply voltage (3.3, 5V is recommended, but not recommended)

GDN: Grounding point

SIO_C SCCB: Control clock of the interface (Note: some low-level microcontrollers require pull-up control, similar to the I2C interface)

SIO_D SCCB: serial data input (output) of the interface (Note: some low-level microcontrollers require pull-up control, similar to the I2C interface)

VSYNC: frame sync signal (output signal) HREF line sync signal (output signal)

PCLK: pixel clock (output signal)

XCLCK: clock signal (input signal)

D0-D7: Data port (output signal)

RESTE: Reset port (normal use pull high)

PWDN: Power selection mode (normal use pull low)