
VT8231
Preliminary Revision 0.8
October 29, 1999
-
81-
Function 3 Registers - USB Controller Ports 2-3
7HFKQRORJLHV,QF
:H &RQQHFW
USB-Specific Configuration Registers
Offset 40 - Miscellaneous Control 1 ................................ RW
7
PCI Memory Command Option
0
Support Memory-Read-Line, Memory-Read-
Multiple, & Memory-Write-&-Invalidate.... def
1
Only support Mem Read, Mem Write Cmds
6
Babble Option
0
Automatically disable babbled port when EOF
babble occurs..........................................default
1
Don
’
t disable babbled port
5
PCI Parity Check Option
0
Disable PERR# generation.....................default
1
Enable parity check and PERR# generation
4
Frame Interval Select
0
1 ms frame..............................................default
1
0.1 ms frame
3
USB Data Length Option
0
Support TD length up to 1280................default
1
Support TD length up to 1023
2
USB Power Management
0
Disable USB power management...........default
1
Enable USB power management
1
DMA Option
0
8 DW burst access with better FIFO latencydef
1
16 DW burst access (original performance)
0
PCI Wait States
0
Zero wait ................................................default
1
One wait
Offset 41 - Miscellaneous Control 2 ................................ RW
7
USB 1.1 Improvement for EOP
0
USB Specification 1.1 Compliant..........default
If a bit stuffing error occurs before EOP, the
receiver will accept the packet
1
USB Specification 1.0 Compliant
If a bit stuffing error occurs before EOP, the
receiver will ignore the packet
6-5
Reserved (Do Not Program)
....................default = 0
4
Hold PCI Request for Successive Accesses
0
Disable
1
Enable....................................................default
Setting this bit to
“
enable
”
causes the system to treat
the USB request as higher priority
3
Frame Counter Test Mode
0
Disable...................................................default
1
Enable
2
Trap Option
0
Set trap 60/64 status bits only when trap 60/64
enable bits are set. .................................default
1
Set trap 60/64 status bits without checking
enable bits
1
A20gate Pass Through Option
0
Pass through A20GATE command sequence
defined in UHCI ....................................default
1
Don
’
t pass through Write I/O port 64 (ff)
0
USB IRQ Test Mode
0
Normal Operation..................................default
1
Generate USB IRQ