Chapter 1 19
Introduction
System displays
FPGA configuration and status
The SMUC is programmed by a serial data transfer from EEPROM upon
utility board power-up. If the transfer does not complete properly, the
SMUC cannot configure itself and many environmental conditions
cannot be monitored. The power-on circuit monitors both the SMUC and
SPUC and does not power up the system, if they are not configured
correctly.
Board over-temperature
On each board in the node, there is one temperature sensor that detects
board overheating. The sensors are bussed together into four-node
quadrants, along with the MIB, and applied to the SMUC.
Fan sensing
The V2500 node has up to six fans, but only four may be configured.
Sensors in the fans determine if the fans are running properly. The
SMUC waits 12.8 seconds for the fans to spin up after power-up before
monitoring them. It is assumed that the unconfigured fans do not report
errors.
Power failure
Because a power failure on a board could cause damage to other boards,
a mechanism on each board detects 3.3-Volt failures on each board.
Power failures are considered environmental errors, and the system is
powered down after they are detected.
MidPlane Interface Board (MIB) power failure
If the MIB power fails, the power-on circuit powers down the entire node.
The Utilities board is still active, but the power-on circuit displays the
power failure condition and disables all Utilities board outputs that drive
the node. This condition persists until power is cycled on the Utilities
board.
48-Volt maintenance
There are four 48-Volt power supplies; three are required, and one is a
redundant source. Each sends a signal to the power-on circuit. If any
supply fails at any time, the circuit asserts the 48-V maintenance line to
