Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
1003
Clocking and Reset—Intel
®
81341 and 81342
Table 633. Reset Strap Signals (Sheet 1 of 2)
Name
Description
BOOT_WIDTH_8#
PBI Boot Bus Width: I
ndicates default bus width for the PBI Memory Boot
window.
0 = 8 bits wide (Requires pull-down resistor)
1 = 16 bits wide (Default mode)
CFG_CYCLE_EN#
Configuration Cycle Enable: Determines when the PCI interface retries
configuration cycles until.
0 = Configuration Cycles enabled (Requires pull-down resistor)
1 = Configuration Retry enabled (Default mode)
PCI-X Interface
Configuration cycles are claimed and terminated with a retry status.
PCI Express Interface
Configuration requests result in a completion TLP with Configuration Retry Status
(CRS).
HOLD_X0_IN_RST#
Core 0 Processor Reset Mode: This strap is latched at the trailing edge of reset
and reflected in Core 0 Processor Reset bit in function 0. See
“Intel XScale® Processor Reset Mechanism”
for more details.
When asserted, the associated Intel XScale
®
processor is held in reset until
software clears the Core 0 Processor Reset bit.
0 = Hold in reset (Requires pull-down resistor)
1 = Don’t hold in reset (Default mode).
HOLD_X1_IN_RST#
Core 1 Processor Reset Mode: This strap is latched at the trailing edge of reset
and reflected in Core 1 Processor Reset bit in function 0. See
“Intel XScale® Processor Reset Mechanism”
for more details.
When asserted, the associated Intel XScale
®
processor is held in reset until
software clears the Core 1 Processor Reset bit.
0 = Hold in reset (Requires pull-down resistor)
1 = Don’t hold in reset (Default mode).
MEM_FREQ[1:0]
Memory Frequency: Determines the frequency of the DDR2 SDRAM memory
subsystem.
MEM_FREQ[1:0]
00
Reserved
01
Reserved
10
DDR-II SDRAM @ 533MHz
11
DDR-II SDRAM @ 400MHz (default)
INTERFACE_SEL_PCIX#
Selects the active interface and determines the address map for the PMMR
registers. See the MMR chapter for details.
0 = PCI-X is active
1 = PCI Express is active (default mode)
When both interfaces are active, this strap selects the ATU that is function 0 in the
internal address map
Note:
For dual interface designs, INTERFACE_SEL_PCIX# must be set
consistent with
PCIE_RC#
/
PCIX_EP#
. When operating with one
interface as an endpoint and the other interface as a root complex.
INTERFACE_SEL_PCIX# must correspond to the end point interface.
PCIE_RC#
PCI Express Root Complex: determines when the PCI Express interface operates
as an endpoint or root complex.
0 = Root Complex (Requires pull-down resistor)
1 = Endpoint (Default Mode).
Note:
Setting both
PCIE_RC#
and
PCIX_EP#
to endpoint is unsupported and
will result in unspecified operation.
PCIX_EP#
PCI-X End Point: determines when the PCI-X interface operates as an endpoint or
central resource.
0 = Endpoint (Requires pull-down resistor)
1 = Central Resource (Default mode)
Note:
Setting both
PCIE_RC#
and
PCIX_EP#
to endpoint is unsupported and
will result in unspecified operation.
PCIXM1_100#
PCI Bus Mode 1 100MHz Enable: limits the maximum PCI-X mode operating
frequency to 100MHz while in mode1. Only used when ATU is acting as the central
resource for the PCI domain.
0 = Limit maximum frequency to 100MHz.(Requires pull-down resistor)
1 = 133MHz enabled (Default mode)