SECTION 3
PCI 9080
FUNCTIONAL DESCRIPTION
PLX Technology, Inc., 1997
Page 37
Version 1.02
A Done Status Bit in the Control/Status Register can be
used to determine whether the interrupt is
A done interrupt
The result of a transfer for a descriptor in a chain
that is not yet complete
Mode Register of a channel enables a done interrupt. In
chaining mode, a bit in the Next Descriptor Pointer
Register of the channel (loaded from local memory)
specifies whether to generate an interrupt at the end of
the transfer for the current descriptor.
A DMA channel interrupt is cleared by writing a 1 to the
Clear Interrupt bit in the DMA Command/Status Register
(refer to Table 4-72[3] and Table 4-73[3]).
3.12.3 PCI SERR# (PCI NMI)
PCI 9080 generates an SERR# pulse if parity checking
is enabled in the PCI Command Register and it detects
an address parity error or the Generate SERR# Bit in the
Interrupt Control/Status Register (refer to Table 4-58) is
0 and a 1 is written.
SERR# output can be enabled or disabled with PCI
Command Register.
3.12.4 Local LSERR# (Local NMI)
LSERR# interrupt output is asserted if the following
occurs:
PCI Bus Target Abort or Master Abort status bit is
set in the PCI Status configuration register
Parity error status bit is set in the PCI Status
configuration register
Messaging outbound free queue overflows
If parity error checking is enabled in the PCI Command
Register, PCI 9080 sets the Master Detected Parity Error
Status bit in the PCI Status configuration register (refer
to Table 4-12) if it detects one of the following:
Parity error during a PCI 9080 master read
PCI bus signal PERR# being asserted during a PCI
9080 master write
PCI 9080 sets a parity error bit in the PCI Status
configuration register (refer to Table 4-12) if it detects
one of the following:
Data parity error during a PCI 9080 master read
Data parity error during a slave write access to the
PCI 9080
Address parity error
The PCI 9080 Interrupt Control/Status Register (refer to
Table 4-58) can be used to individually enable or disable
LSERR# for an abort or parity error. LSERR# is a level
output that remains asserted as long as the Abort or
Parity Error Status bits are set.
3.13 I
2
0 COMPATIBLE MESSAGE UNIT
Messaging Unit supplies two paths for messages, two
inbound FIFOs to receive messages from the primary
PCI bus and two outbound FIFOs to pass messages to
the primary PCI bus. Refer to I
2
O Architecture
Specification v1.5 or details.
Figure 3-22 and Figure 3-23 illustrate information about
the I
2
0 architecture.
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Figure 3-22. I
2
O System Architecture
Figure 3-23. I
2
O Software Architecture