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Table 5. JW1 Jumper Settings (Sheet 2 of 2)
Jumper
3-4
5-6*
3.5
Firmware
The latest release of the 8x931HA firmware can be downloaded from the Intel software support
website listed in Table 1 on page 5.
Refer to Table 1 for the Intel USB Specification Update website location to learn about any known
errata for the CHUB
3.6
Design Notes
The CHUB is only intended to provide an evaluation platform and reference design for use in
constructing a USB HUB that will incorporate Intel's 8x931HA USB Peripheral Controller. The
CHUB is not intended to be a commercial-ready device. The intent of the CHUB is to provide a
starting point to IHVs for development of their products. Users of the CHUB are responsible for all
designs they may create with the CHUB.
Some trade-offs should be noted which were made to incorporate flexibility into the CHUB for
evaluation purposes. Because of this, some items should be noted if this design is to be used as a
base for an actual production hub. These items are listed below and may not be the only items to
consider. Users need to perform their own testing of their designs to ensure that all necessary USB
specifications are met.
3.6.1
Suspend Current
THe CHUB is designed to provide the user the flexibility to operate in stand alone mode or in
expanded mode. Stand alone mode is defined as running firmware from on chip ROM. Expanded
mode is defined as running firmware from an external EPROM.
During validation testing in external EPROM mode, the CHUB suspend current was measured at
8.0-10.0 mA. This was primarily due to the extra current drawn by the EPROM and latch. This is in
violation of USB spec which specifies a maximum suspend current of 500 micro amps. When
running from on-chip ROM, the suspend current was well within spec.
This should not pose a problem because in an actual production hub, the ROM code would reside
in internal memory.
1. As of the printing date of this document, it was discovered that the Microsoft Memphis* Beta 3 operating system was incorrectly using the
values set in the PortPwrCtrlMask field to determine which downstream ports to issue "Set Port Power" commands to upon device
enumeration/configuration. This bug in the beta version, in conjunction with the values reported in the hub's port power control mask
field, caused the operating system to fail to issue "Set Port Power" commands to the downstream ports on Intel's 8x931Hx hub peripheral
controller. Refer to http://developer.intel.com/design/usb/specupdt for the prescribed workaround.
.
Advance Information Datasheet
Mode
ROM enabled
ROM enabled
1
specification.
8x931HA USB Customer Hub
Description
Enable or disable via software
(P3.1)
Hardware enabled (*default position)
(CE# = 0)
9
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