SECTION 4
PCI 9080
REGISTERS
PLX Technology, Inc., 1997
Page 55
Version 1.02
4.3 PCI CONFIGURATION REGISTERS
All registers may be written to or read from in byte, word, or Lword accesses.
4.3.1 (PCIIDR; PCI:00h, LOC:00h) PCI Configuration ID Register
Table 4-10. (PCIIDR; PCI:00h, LOC:00h) PCI Configuration ID Register
Field
Description
Read
Write
Value after Reset
15:0
Vendor ID. Identifies device manufacturer. Defaults to the PCI SIG issued vendor
ID of PLX (10B5h) if no serial EEPROM is present and pin NB# (no local bus
initialization) is asserted low.
Yes
Local/
Serial
EEPROM
10B5h
or
0
31:16
Device ID. Identifies the particular device. Defaults to the PLX part number for PCI
interface chip (PCI 9080) if no serial EEPROM is present and pin NB# (no local bus
initialization) is asserted low.
Yes
Local/
Serial
EEPROM
9080h
or
0
4.3.2 (PCICR; PCI:04h, LOC:04h) PCI Command Register
Table 4-11. (PCICR; PCI:04h, LOC:04h) PCI Command Register
Field
Description
Read
Write
Value after Reset
0
I/O Space. Value of 1 allows device to respond to I/O space accesses. Value of 0
disables device from responding to I/O space accesses.
Yes
Yes
0
1
Memory Space. Value of 1 allows device to respond to memory space accesses.
Value of 0 disables device from responding to memory space accesses.
Yes
Yes
0
2
Master Enable. Value of 1 allows device to behave as a bus master. Value of 0
disables device from generating bus master accesses. This bit must be set for the
PCI 9080 to perform Direct Master or DMA cycles.
Yes
Yes
0
3
Special Cycle. (This bit is not supported.)
Yes
No
0
4
Memory Write/Invalidate Enable Bit. Value of 1 enables memory write/invalidate.
Value of 0 disables memory write/invalidate. (Refer to the DMA Mode Registers
(DM, DMAMODE0, and DMAMODE1) bit 13.) (Refer to Table 4-43[13],
Table 4-62[13], and Table 4-67[13], respectively.)
Yes
Yes
0
5
VGA Palette Snoop. (This bit is not supported.)
Yes
No
0
6
Parity Error Response. Value of 0 indicates a parity error is ignored and operation
continues. Value of 1 indicates parity checking is enabled.
Yes
Yes
0
7
Wait Cycle Control. Controls whether the device performs address/data stepping.
Value of 0 indicates device never does stepping. Value of 1 indicates device always
does stepping.
Note:
Hardcoded to 0.
Yes
No
0
8
SERR# Enable. Value of 1 enables SERR# driver. Value of 0 disables SERR#
driver.
Yes
Yes
0
9
Fast Back-to-Back Enable. Indicates type of fast back-to-back transfers Master can
perform on bus. Value of 1 indicates fast back-to-back transfers can occur to any
agent on bus. Value of 0 indicates fast back-to-back transfers can only occur to
same agent as previous cycle.
Yes
No
0
15:10
Reserved.
Yes
No
0