SECTION 3
PCI 9080
FUNCTIONAL DESCRIPTION
PLX Technology, Inc., 1997
Page 12
Version 1.02
3. FUNCTIONAL DESCRIPTION
Functional operation described can be changed or
modified, depending on the register configuration.
3.1 RESET
3.1.1 PCI Bus Input RST#
PCI bus RST# input pin is a PCI host reset. It causes all
PCI bus outputs to float, resets the entire PCI 9080 and
causes the local reset output, LRESETo#, to be
asserted. If you have a PCI host, Table 4-11[2:0] (Master
Enable, Memory Space, I/O Space) is programmed by
the host after initialization is complete (Table 4-
59[31]=1). (Refer to Figure 3-1.)
!"#$
% &
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Figure 3-1. Reset and Initialization Process
3.1.2 Software Reset LRESETo#
When asserted, the LRESETo# Software Reset bit
(Table 4-59[30]) resets PCI 9080 Local Configuration
and Local DMA Registers. However, it does not reset the
PCI Configuration and Shared Runtime Registers. When
the bit is set, PCI 9080 responds to PCI accesses, but
not to local accesses. PCI 9080 remains in this condition
until PCI host clears the bit. The serial EEPROM is
reloaded if Table 4-59[29] is set.
3.1.3 Local Bus Input LRESETi#
When asserted, the LRESETi# input resets the local bus
portion of PCI 9080, clears all local configuration and
DMA registers and causes LRESETo# output to be
asserted.
3.1.4 Local Bus Output LRESETo#
LRESETo# is asserted when PCI bus RST# input is
asserted, the LRESETi# input is asserted, or the
software reset bit in the Init Control Register is set to 1.
3.1.5 Software Reset
A host on the PCI bus can set the software reset bit in
the Init Control Register to reset PCI 9080 and assert the
LRESETo# output. All local configuration and DMA
registers reset. PCI configuration registers do not reset.
When the software reset bit is set, PCI 9080 responds to
PCI accesses, but not to local bus accesses. PCI 9080
remains in this reset condition until the PCI host clears
the bit.
Note:
because the local bus is in a reset state.
The local side cannot clear this reset bit
3.2 PCI 9080 INITIALIZATION
PCI 9080 configuration registers can be programmed by
an optional serial EEPROM and/or by a local processor,
as listed in Table 3-1. The serial EEPROM can be
reloaded by setting bit 29 of (LOC:ECh), Serial
EEPROM Control Register (refer to Table 4-59[29]).
In general, PCI 9080 retries all PCI cycles until the
“Local Init Done bit” is set or NB# is low.
Note:
accessed by the PCI host processor after power-on.
Internal configuration register can also be