Description 19
SMI and NMI Routing
There are numerous SMI sources and all are routed to the PIIX4. Software must configure the
PIIX4 SMI source pins to control whether SMI is propagated through to the processor via its
H_SMI input or not. For details on the fault conditions that cause SMI to occur, consult the data
sheets of the SMI source ICs. The SMI routing on the server board is described in Table 6. Note
that some PIIX4 inputs have several sources. Schematic signal names are in parenthesis.
Table 6. SMI and NMI Routing
SMI Source PIIX4 Input Pin
BX Chipset PCI SERR# - used for ECC Errors (P_SERR#) EXT_SMI#
LAN PCI SERR# (P_SERR#) EXT_SMI#
All three PCI Slot’s SERR# (P_SERR#) EXT_SMI#
Gluechips EXTSMI# output – used for +5 VSB errors GPI13
Gluechips EXTSMI# output – Through buffer to (P_SERR#) EXT_SMI#
LAN1 PCI PME# (P_PME#) GPI1
LAN2 PCI PME# (P_PME#) GPI1
All three PCI slot’s PME# (P_PME#) GPI1
Super I/O Serial Interrupt SMI – used for watchdog timer
(SER_IRQ)
SER_IRQ
Super I/O PME# (SIO_RIA#) – originally from WOR header or
ext. modem
RIAB
Wake on LAN header – used for Wake on LAN (WOL#) LID
The Gluechips EXT_SMI# output is also connected to the PIIX4 GPI13 pin to provide a status of
the Gluechips EXT_SMI# signal.
All NMI generation on the server board is under software control. Writes to PIIX4 GPO17 are
routed to the PIIX4 IOCHK# input which may be configured to cause a NMI to occur. Thus,
software may cause a NMI to occur by pulsing GPO17 active.
The TR440BX server board BIOS SMI handler detects SMI events, logs the events, and elevates
selected events to NMI level.
Power Connector
When used with an ATX-compliant power supply that supports remote power on/off, the server
board can turn off the system power through software control.
Speaker
A 47-ohm inductive speaker is mounted on the server board. The speaker provides audible error
code (beep code) information during the Power-On Self-Test (POST).