What this 256 Mbit NOR Flash brings to the board
It communicates over a SPI bus with Quad I/O support, clocking at 133 MHz.
133 MHz Quad I/O — read bandwidth without the pin count
Quad I/O uses four data lines instead of one, quadrupling the theoretical throughput per clock cycle compared to standard SPI. At 133 MHz, the effective read rate is high enough for execute-in-place (XIP) firmware on many MCUs, reducing the need for a separate SRAM shadow. The interface is backward-compatible with standard SPI for legacy controllers that don't support quad mode. Keep the PCB trace length matched across the four data lines to avoid skew at 133 MHz.
Package and footprint: 24-BGA 6x8 mm
The 24-ball BGA measures 6x8 mm. It requires a multi-layer PCB with microvias or blind vias for routing. The package is surface-mount only.