Intel IXP43X manual Boot/Reset Strapping Configuration Sheet 2

Hardware Design Guidelines—Intel®IXP43X Product Line of Network Processors

Table 6.	Boot/Reset Strapping Configuration (Sheet 2 of 2)
Name		Function			Description
			1	= EX_IOWAIT_N is sampled during the read/write expansion bus cycles for Chip
			Select 0.
			0	= EX_IOWAIT_N is ignored for read and write cycles to Chip select 0 if
			EXP_TIMING_CS0 is configured to Intel mode that is mentioned in Intel® IXP43X
			Product Line of Network Processors Datasheet and Intel® IXP43X Product Line of
			Network Processors Developer’s Manual.
			Typically, IOWAIT_CS0 must be pulled down to Vss when attaching a Synchronous
EX_ADDR[10]		IOWAIT_CS0	Intel StrataFlash® on Chip Select 0 since the default mode for EXP_TIMING_CS0 is
			Intel mode and EX_IOWAIT_N is an unknown value for Synchronous Intel
			StrataFlash.
			If the board does not connect the Synchronous Intel StrataFlash WAIT pin to
			EX_WAIT_N (and the board guarantees EX_IOWAIT_N is pulled up), the value of
			IOWAIT_CS0 is a don’t-care, since EX_IOWAIT_N will not be asserted.
			When EXP_TIMING_CS0 is reconfigured to Intel Synchronous mode during
			boot-up (for synchronous Intel chips), the expansion bus controller ignores
			EX_IOWAIT_N during read and write cycles since the WAIT functionality is
			determined from the EXP_SYNCINTEL_COUNT and EXP_TIMING_CS registers.
EX_ADDR[9]		EXP_MEM_DRIVE	Refer to table found in EX_ADDR[5].
			Controls the USB clock select.
			1	= USB Host/Device clock is generated internally
EX_ADDR[8]		USB Clock	0	= USB Device clock is generated from GPIO[0].
			When generating a spread spectrum clock on OSC_IN, GPIO[1] can be driven from
			the system board to generate a 48 MHz clock for the USB Host.
			Selects the data bus width of the FLASH memory device found on Chip Select 0.
EX_ADDR[7]		32_FLASH	Refer to 8/16_FLASH bit (Bit 0) of this register as well.
			0	= 8 or 16-bit data bus size (must be pulled down during address strapping)
			1	= not supported
EX_ADDR[6]		(Reserved)	(Reserved)
			Expansion bus low/medium/high drive strength. The drive strength depends on
			EXP_DRIVE and EXP_MEM_DRIVE configuration bits.
			EXP_MEM_DRIVE		EXP_DRIVE	Expansion drive strength
EX_ADDR[5]		EXP_DRIVE	------------------------------------------------------------------------------------
				0	0	Reserved
				0	1	Medium Drive
				1	0	Low Drive
				1	1	High Drive
			Sets the clock speed of the PCI Interface
EX_ADDR[4]		PCI_CLK	0	= 33 MHz (must be pulled down during address strapping)
			1	= not supported
EX_ADDR[3]		(Reserved)	(Reserved). EX_ADDR[3] must not be pulled down during address strapping. This
			bit must be written to ‘1’ if performing a write to this register.
			Enables the PCI Controller Arbiter
EX_ADDR[2]		PCI_ARB	0	= PCI arbiter disabled
			1	= PCI arbiter enabled
			Configures the PCI Controller as PCI Bus Host
EX_ADDR[1]		PCI_HOST	0	= PCI as non-host
			1	= PCI as host
			Specifies the data bus width of the FLASH memory device found on Chip Select 0.
EX_ADDR[0]		8/16_FLASH	8/16_FLASH		Data bus size
				0	16-bit
				1	8-bit

	Intel® IXP43X Product Line of Network Processors
April 2007	HDG
Document Number: 316844; Revision: 001US	23