W25Q64 SPI Flash Memory Module 64Mbit

A microcontroller's own flash memory holds its program, not necessarily the data that program generates, which is where an external flash chip like the W25Q64 comes in: 8MByte of dedicated storage reachable over a fast SPI connection, running its clock up to 104MHz. That is enough room for logged sensor data, configuration that needs to survive firmware updates, or small media assets a project needs to keep separate from its own code space.

At 2.7V to 3.6V operating voltage and 4mA current draw, it fits comfortably into low-power IoT designs without becoming the dominant power draw on the board, and the SPI interface means it shares wiring conventions with SD card modules and other SPI peripherals a project might already be using.

Common uses are data logging that needs to persist independent of the microcontroller's own memory, storing configuration or calibration data, and IoT projects needing local buffering before data is sent onward.