Intel MPCMM0002 manual Filter Tray, Power Switch

MPCMM0002 CMM—Backplane Considerations

Figure 12. CDM Power Input

CDM 1 CDM 2

6.2.3Filter Tray

The CMM also provides direct support for a filter tray. The CMM provides signals to handle a filter presence switch, two thermistors, and a tricolor LED.

The filter presence switch is typically a mechanical switch that connects the AF_PRES# signal to ground when an air filter is installed in the chassis. The switch is debounced in software.

The two thermistor inputs provide redundant temperature readings to the CMM. The thermistors should be a NTC (negative thermocouple) device like the US Sensor* USX2257 thermocouple (http://www.ussensor.com/). For maximum accuracy, a dedicated logic ground reference signal AFTREF is provided to isolate localized perturbations to logic ground. Chassis designers should use the AFTREF signal exclusively for these thermocouples and should route the two temperature signals and the reference signal in close proximity.

6.2.4Power Switch

The CMM has support for an optional soft power switch. This dual-pole input signal can be used to signal the CMM to gracefully shut down the elements within the chassis. Both poles of this switch are debounced in software. If only one contact on the switch closes, the CMM flags this as an error and generates a system event log entry.

These direct drive capabilities of the CMM are summarized in the table below. All the outputs are protected via OR-ing diodes, as shown in Figure 12.

Intel NetStructure® MPCMM0002 Chassis Management Module
Hardware TPS	July 2007
30	Order Number: 309247-004US