
Chapter 4
Registers
293
24674
Rev. 3.00
April 2003
AMD-8111 HyperTransport I/O Hub Data Sheet
AMD Preliminary Information
Default:
Bits
31:24 Reserved. Hardwired to 00h.
23:16
ITC. Interrupt Threshold Control
.
Read-write. This
fi
eld is used by system software to select the maximum rate at which the host
controller issues interrupts. The only valid values are de
fi
ned below. If software writes an invalid value
to this register, the results are unde
fi
ned.
Value
Maximum Interrupt Interval
00h
Reserved
01h
1 micro-frame
02h
2 micro-frames
04h
4 micro-frames
08h
8 micro-frames (default, equates to 1 ms)
10h
16 micro-frames (2 ms)
20h
32 micro-frames (4 ms)
40h
64 micro-frames (8 ms)
Software modi
fi
cations to this bit while HCHalted bit is equal to zero results in unde
fi
ned behavior.
15:12 Reserved. Hardwired to 0000b.
11
ASPME. Asynchronous Schedule Park Mode Enable
.
Read-write. Hard wired to =b, Software uses this bit to enable or disable Park mode. When this bit is
one, Park mode is enabled. When this bit is a zero, Park mode is disabled.
10
Reserved. Hardwired to 0b.
9:8
ASPMC. Asynchronous Schedule Park Mode Count
.
Read-write.Hard wired to 0h, It contains a count of the number of successive transactions the host
controller will execute from a high-speed queue head on the Asynchronous schedule before
continuing traversal of the Asynchronous schedule. See EHCI Spec, section 4.10.3.2 for full
operational details. Valid values are 1h to 3h. Software must not write a zero to this bit when Park
Mode Enable is a one as this results in unde
fi
ned behavior.
7
LITE_HCRESET. Light Host Controller Reset
.
Read-write. It allows the driver to reset the EHCI controller without affecting the state of the ports or
the relationship to the companion host controllers. A host software read of this bit as zero indicates
the Light Host Controller Reset has completed and it is safe for host software to re-initialize the host
controller. A host software read of this bit as a one indicates the Light Host Controller Reset has not
yet completed.
6
IAAD. Interrupt on Async Advance Doorbell
.
Read-write. This bit is used as a doorbell by software to tell the host controller to issue an interrupt
the next time it advances asynchronous schedule. Software must write a 1b to this bit to ring the
doorbell.
5
ASE. Asynchronous Schedule Enable
.
Read-write. This bit controls whether the host controller skips processing the Asynchronous
Schedule. 0= Do not process the Asynchronous Schedule. 1= Use the ECAP48 register to access
the Asynchronous Schedule.
0008_0000h.
Description
Attribute:
See below.