Intel IXP43X manual Signal Interface, USB Host Signal Recommendations

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

3.7.1Signal Interface

Table 13.	USB Host Signal Recommendations
Name		Type	Pull
			Up/	Description
		Field
			Down
				Positive signal of the differential USB receiver/driver for the USB host interface.
				Use an 20Ω series termination resistor at the source.
USB_P0_POS		I/O	Yes	When this interface/signal is enabled and is not being used in a system design, the
				interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse and is not being used in a system design, it
				is not required for any connection. Refer to Expansion Bus Controller chapter of the
				Intel® IXP43X Product Line of Network Processors Developer’s Manual.
				Negative signal of the differential USB receiver/driver for the USB host interface.
				Use an 20Ω series termination resistor at the source.
USB_P0_NEG		I/O	Yes	When this interface/signal is enabled and is not being used in a system design, the
				interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse and is not being used in a system design, it
				is not required for any connection. Refer to Expansion Bus Controller chapter of the
				Intel® IXP43X Product Line of Network Processors Developer’s Manual.
USB_P0_PWREN		O	No	Enables the external VBUS power source.
				External VBUS power is in over current condition
				When this interface/signal is enabled and is not being used in a system design, the
USB_P0_OC		I	No	interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse and is not being used in a system design, it
				is not required for any connection. Refer to Expansion Bus Controller chapter of the
				Intel® IXP43X Product Line of Network Processors Developer’s Manual.
				Positive signal of the differential USB receiver/driver for the USB host interface.
				Use an 20Ω series termination resistor at the source.
USB_P1_POS		I/O	Yes	When this interface/signal is enabled and is not being used in a system design, the
				interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse. Refer to Expansion Bus Controller chapter
				of the Intel® IXP43X Product Line of Network Processors Developer’s Manual.
				Negative signal of the differential USB receiver/driver for the USB host interface.
				Use an 20Ω series termination resistor at the source.
USB_P1_NEG		I/O	Yes	When this interface/signal is enabled and is not being used in a system design, the
				interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse and is not being used in a system design, it
				is not required for any connection. Refer to Expansion Bus Controller chapter of the
				Intel® IXP43X Product Line of Network Processors Developer’s Manual.
USB_P1_PWREN		O	No	Enable the external VBUS power source.
				External VBUS power is in over current condition
				When this interface/signal is enabled and is not being used in a system design, the
USB_P1_OC		I	No	interface/signal should be pulled low with a 10-KΩresistor. When this interface is
				disabled through the USB Device soft fuse and is not being used in a system design, it
				is not required for any connection. Refer to Expansion Bus Controller chapter of the
				Intel® IXP43X Product Line of Network Processors Developer’s Manual.

A typical implementation of a USB interface Host down-stream is shown in Figure 9. The Host controller cannot be used as a Device controller.

Note: Depending on the data rate required, Low-speed, Full-speed or High-speed, the 1.5K resistor shown near the device interface must be connected on the D+ or D-.

Speed configuration at the Device can be set as stated in note 1 and 2 below. For more details, refer to the Universal Serial Bus Specification, Revision 2.0.

Note:

1.If a 1.5-KΩ,pull-up resistor is connected to USB_P_POS line, the USB port is identified as Full-speed and High-speed mode.

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