Front Panel Unit (FPU)

The Front Panel Unit (FPU) contains the necessary connectors, switches,

logic, and LED indicators for the Front Panel. For every type of Trusted I/O

Module, the FPU contains the Slice Healthy, Active/Standby, the Educated

LED indicators, and the Module removal switches. Additional bicolor LEDs

provide status indication for the individual I/O signals. Serial data interfaces

connect the FPU to each of the HIU slices to control the LED status indicators

and monitor the Module removal switches.

The FIU receives isolated power from the HIU for logic. The FIU provides

additional power conditioning for the operational voltages required by the

FIU circuitry. An isolated 6.25 Mbit/sec serial link connects each FIU to one of

the HIU slices.

The FIU also measures a range of onboard “housekeeping” signals that assist

in monitoring the performance and operating conditions of the Module.

These signals include power supply voltages, current consumption, onboard

reference voltages and board temperature.