12. Register Descriptions
248
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
12.4
Bit Ordering and Endian Ordering
The register tables in
“Register Descriptions” on page 248
provide bit ordering in both PCI
little-endian and PowerPC big-endian. The register table from the
“PCI-1 Control and Status Register.”
is repeated here. The “PCI Bits” in the left hand column give the addressing of the register
bits when the register is accessed from the PCI bus in little-endian mode. The “PB Bits” in the far right
hand column give the addressing of the register bits when the register is accessed from the Processor
Bus in big-endian mode.
Please consult
for a full endian discussion.
12.5
Register Descriptions
In the following detailed descriptions of each register, the shaded register bits are different for the Dual
PCI PowerSpan II and Single PCI PowerSpan II
describes the abbreviations used in the register descriptions.
PCI
Bits
Function
PB
Bits
31-24
D_PE
S_
SERR
R_MA
R_TA
S_TA
DEVSEL
MDP_D
0-7
23-16
TFBBC
0
DEV66
CAP_L
PCI Reserved
8-15
15-08
PCI Reserved
MFBBC
SERR_EN
16-23
07-00
WAIT
PERESP
VGAPS
MWI_
EN
SC
BM
MS
IOS
24-31
Throughout the manual, register fields are given assuming PCI little-endian bit
ordering. The user must consult the register table to obtain the corresponding
PowerPC big-endian bit ordering.
Table 65: Abbreviations used in Register Descriptions
Abbreviation
Description
G_RST
General Reset (Active when either PB_RST, P1_RST, or P2_RST is asserted)
PB_RST
Processor Bus Reset
P1_RST
PCI-1 (P1) Reset
P2_RST
PCI-2 (P2) Reset
Px_RST
PCI-1 or PCI-2 Reset