9. Resets, Clocks and Power-up Options
172
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
The options PWRUP_PB_ARB_EN, PWRUP_P1_ARB_EN, and PWRUP_P2_ARB_EN are used to
select between an external arbiter or a PowerSpan II arbiter for each interface.
PWRUP_PRI_PCI designates either PCI-1 or PCI-2 as being connected to the Primary PCI Interface
segment in the system (see
for more details on Primary PCI Interface
functionality).
When PWRUP_P1_R64_EN is enabled, the PowerSpan II PCI-1 interface drives P1_REQ64# during
assertion of P1_RST# to signal the presence of a 32-bit or
64-bit data path to all agents on the PCI-1 bus segment. This option must only be enabled when
PowerSpan II
is the Central Resource in the system.
The option PWRUP_BOOT enables the system designer to control boot from PCI or from the
processor bus. Whether this feature is enabled or disabled is dependent on system requirements (refer
to
for more information).
By enabling option PWRUP_BYPASS_EN, all PLLs in the design are bypassed. Typically, this option
must be disabled (PLL in use) in the system.
In the Single PCI PowerSpan II, the following power-up options are not configurable:
•
PWRUP_P2_ARB_EN
— no PCI-2 arbiter
PCI-1 REQ64 Enable
(PWRUP_P1_R64_EN)
Disable
P1_REQ64_
INT[4]_=1
PB_D[4]=0
P1_R64_EN=0
Enable
P1_REQ64_
INT[4]_=0
PB_D[4]=1
P1_R64_EN=1
Boot select
(PWRUP_BOOT)
PB Boot
INT[3]_=1
PB_D[5]=0
PCI_BOOT=0
PCI Boot
INT[3]_=0
PB_D[5]=1
PCI_BOOT=1
7400 Mode Enable
(PWRUP_7400_MODE)
Disable
7400_Mode
INT[2]_=1
PB_D[6]=0
7400_MODE=0
Enable
7400_Mode
INT[2]_=0
PB_D[6]=1
7400_MODE=1
PLL Bypass Enable
(PWRUP_BYPASS_EN)
Disable PLL
Bypass
INT[1]_=1
PB_D[7]=0
BYPASS_EN=0
Enable PLL
Bypass
INT[1]_=0
PB_D[7]=1
BYPASS_EN=1
a.
The information in the System Pin column is used when PowerSpan II is in Multiplexed System Pin mode
(see
b.
The information in the PB_D Pin column is used when PowerSpan II is in Configuration Slave mode
(
Table 45: PowerSpan II Power-up Options
Power-up Option
Selection
System Pin
a
PB_D Pin
b
RST_CSR Register