The FPC401 quad port controller serves as a low-speed signal aggregator for common port types such as SFP+, QSFP+, and SAS. The FPC401 aggregates all low-speed control and I2C signals across four ports and presents a single easy-to-use management interface to the host (I2C or SPI). Multiple FPC401s can be used in high-port-count applications with one common control interface to the host. The FPC401 is designed to allow placement on the bottom side of the PCB, underneath the press fit connector, to simplify routing. This localized control of the ports’ low-speed signals cuts system BOM cost by enabling the use of smaller IO count control devices (FPGAs, CPLDs, MCUs) and by reducing routing layer congestion.
The FPC401 is compatible with standard SFF-8431, SFF-8436, and SFF-8449 low-speed management interfaces, including a dedicated 100/400 kHz I2C interface to each port. Additional general-purpose pins are available to perform functions such as driving port status LEDs or controlling power switches. The LED drivers have convenience features such as programmable blinking and dimming. The interface to the host controller can operate on a separate supply voltage between 1.8-V and 3.3-V to support low-voltage I/Os.
The FPC401 can pre-fetch data from user-specified registers in each module, making the data readily accessible to the host through a fast I2C (up to 1 MHz) or SPI (up to 10 MHz) interface. In addition, the FPC401 can trigger an interrupt to the host whenever critical, user-configurable events occur associated with any of the ports under its control. This eliminates the need to continuously poll the modules.