Chapter 1 9
Introduction
Utilities board
Environmental condition detected by power-on
function
The power-on function detects environmental errors (such as ASIC Not
Installed OK or FPGA Not OK). It does not turn on power to the node
until the conditions are corrected. It also detects environmental errors
such as 48-V Fail while the system is powering up and MIB Power Fail
after the system has powered up. If a failure is detected in these two
cases, the power-on circuit turns off power to the system.
Environmental warnings such as 48-Volt maintenance are also detected
by the power-on circuit.
In all cases, the power-on circuit sets an environmental attention light
bar code. The code is prioritized so that it displays the highest priority
error or warning. See “Attention light bar” on page 16 for a list of codes.
Environmental conditions detected by SMUC
The SMUC detects most of the environmental conditions. It samples
error conditions during a time period derived from a local 10-Hz clock
that drives the power-on circuit. It registers all the environmental error
conditions twice and then logically ORs them together. If the conditions
persist for 200 mS, the environmental error bit is set, and an
environmental error interrupt is sent to the SPUC, which sends it on to
the processors. The SMUC then waits 1.2 seconds and commands the
power-on circuit to power down the system.
This same procedure exists for an environmental warning, except that
an environmental warning interrupt is sent and the power-on circuit
does not power down the system.
Ambient air warm Environmental
warning
LED indication, interrupt
48-Volt maintenance Environmental
warning
LED indication, interrupt
Hard error Hard error LED indication, interrupt
Condition Type Action
