The SST26VF016BT uses SuperFlash ESF-3 NOR Flash technology with a split-gate memory cell. In SQI mode, four data lines (SI, SO, SIO2, SIO3) transfer data simultaneously, achieving 4x throughput compared to standard SPI. Commands are clocked in via the SI pin, and addresses and data transfer on all four pins during high-speed operations. The device supports standard SPI commands for backward compatibility, as well as SQI-specific commands for maximum performance. Read operations access the memory array through a page buffer, while program operations use a write buffer to program up to 256 bytes simultaneously. The sector protection mechanism uses individual bit-protection registers to prevent accidental erasure. The hold and write-protect pins provide hardware control for pausing and protecting operations. A global unlock command removes all sector protections at once.