FX2

fx2 refers to the EZ-USB FX2 family of USB 2.0 peripheral controllers developed by Cypress Semiconductor. The devices are designed to let engineers build custom USB peripherals by combining an 8051-compatible microcontroller core with a USB 2.0 device controller and a programmable interface to external logic. The line includes devices such as FX2 and FX2LP, the latter optimized for lower power operation.

Architecture and operation: The FX2 family integrates an 8051-based CPU with on-chip RAM and ROM, a USB 2.0 peripheral controller that supports standard USB device endpoints, and a General Programmable Interface II (GPIF II) that can be configured to connect the FX2 to external hardware such as memories or parallel peripherals. The devices support a Slave FIFO mode that streams data between the USB endpoint buffers and external logic or memory, enabling high-throughput data transfers for instrumentation and data acquisition. Firmware runs on the FX2 to control USB descriptors, endpoint behavior, and GPIF II state machines.

Development: Cypress provided development tools for FX2/FX2LP, including GPIF II Designer to configure the data path, example firmware, and vendor libraries. Programming is typically done in C for the 8051 core, using common IDEs such as Keil or IAR, with debugging aided by Cypress USB drivers and evaluation boards.

Applications and history: The FX2 line was widely used in custom USB devices, data loggers, USB bridges, and various data-transfer roles in the 2000s and 2010s. It has since been complemented or superseded by the FX3 family, which offers USB 3.0 support and newer architecture, though FX2/FX2LP designs remain in service and documented in historical context.