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Hardware Reference Manual 369
Intel
®
IXP2800 Network Processor
Clocks and Reset
Table 149. IXP2800 Network Processor Strap Pins
Signal Name Description
CFG_RST_DIR RST_DIR
PCI_RST direction pin: (Also called PCI_HOST) Need to
be a dedicated pin.
1—IXP2800 Network Processor is the host supporting
central function. PCI_RST_L is output.
0—IXP2800 Network Processor is not central function.
PCI_RST_L is input.
This pin is stored at XSC[31] (XScale_Control register) at
the trailing edge of reset.
CFG_PROM_BOOT GPIO[0]
PCI PROM BOOT Pin:
1—IXP2800 Network Processor will boot from PROM:
Whether Intel XScale
®
core will configure the system or not
will be defined by CFG_PCI_BOOT_HOST strap option.
0—IXP2800 Network Processor will not boot from PROM.
So after host has downloaded image od boot code into
DRAM, Intel XScale
®
core will boot from DRAM address 0.
This pin is stored at XSC[29] (XScale_Control register) at
the trailing edge of reset.
CFG_PCI_BOOT_HOST GPIO[1]
PCI BOOT HOST Pin:
1—IXP2800 Network Processor will configure the PCI
system.
0—IXP2800 Network Processor will not configure the PCI
system.
This pin is stored at XSC[28] (XScale_Control register) at
the trailing edge of reset.
CFG_PCI_ARB GPIO[2]
PCI Arbiter Pin:
1—IXP2800 Network Processor is the arbiter on the PCI
bus.
0—IXP2800 Network Processor is not the arbiter on the
PCI bus.
PLL_MULT[5:0] SP_AD[5:0]
PLL Multiplier
Valid values are 010000-110000 for a multiplier range of 16
– 48. Other values will result in undefined behavior by PLL.
RESET_OUT_STRAP SP_AD[7]
When 1: nRESET_OUT is removed after PLL locks.
When 0: nRESET_OUT is removed by software using bit
IXP_RESET0[17].
CFG_PCI_SWIN[1:0] GPIO[6:5]
SRAM Bar Window:
11—SRAM BAR size of 256 Mbytes
10—SRAM BAR size of 128 Mbytes
01—SRAM BAR size of 64 Mbytes
00—SRAM BAR size of 32 Mbytes
CFG_PCI_DWIN[1:0] GPIO[4:3]
DRAM BAR Window:
11—DRAM BAR size of 1024 Mbytes
10—DRAM BAR size of 512 Mbytes
01—DRAM BAR size of 256 Mbytes
00—DRAM BAR size of 128 Mbytes
CFG_MSF_FREQ_SEL SP_AD[6]
Select source of MSF Tx Clock:
0—TCLK_Ref input pin
1—Internally generated clock