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Technical Reference Guide
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September 1997
5-37
5.8 UNIVERSAL SERIAL BUS INTERFACE
The Universal Serial Bus (USB) interface provides up to 12 Mb/s data transfers between the host
system and peripherals designed with a compatible USB interface. This high speed interface
supports hot-plugging of compatible devices, making possible system configuration changes
without powering down or even rebooting systems. The USB interface supports both
isochronous and asynchronous communications, and integrates a 5 VDC power bus that can
eliminate the need for external powering of small remote peripherals.
5.8.1 USB CONFIGURATION
The USB interface functions as a PCI device (20) within the 82586 component (function 2) and
is configured using PCI Configuration Registers as listed in Table 5-20.
Table 5–20. USB Interface Configuration Registers
Table 5-20.
USB PCI Configuration Registers (82586, Function 2)
PCI Config.
Addr. Register
Reset
Value
00h-01h Vender ID 1106h
02h-03h Device ID 3038h
04h-05h PCI Command 0000h
06h-07h PCI Status 0280h
08h Revision ID 00h
09h Programming I/F 00h
0Ah Sub Class Code 03h
0Bh Base Class Code 0Ch
0Dh Latency Timer 00h
0Eh Header Type 80h
24h-27h I/O Space Base Address All 0’s
3Ch Interrupt Line 00h
3Dh Interrupt Pin 04h
40h Miscellaneous Control 1
41h Miscellaneous Control 2
60h Serial Base Release Number 00h
C0-C1h Legacy Support Reg. (compliant w/UHCI v1.1) 2000h