FW82801EB Intel, FW82801EB Datasheet - Page 219

• Manufacturer Part Number: FW82801EB
• Manufacturer: Intel

Specifications of FW82801EB

• Lead Free Status / RoHS Status: Not Compliant

5.20.3.2.2
5.20.4
5.20.5
Intel
®
82801EB ICH5 / 82801ER ICH5R Datasheet
Note: The ADE does not fetch data when a QH is encountered in the Ping state. An Ack handshake in
Note: Once the ADE checks the length of an asynchronous packet against the remaining time in the
Note: Once the ADE detects an “empty” asynchronous schedule as described in Section 4 of the
response to the Ping results in the ADE writing the QH to the Out state, which results in the
fetching and delivery of the Out Data on the next iteration through the asynchronous list.
microframe (late-start check) and decides that there is not enough time to run it on the wire, then
the EHC stops all activity on the USB ports for the remainder of that microframe.
Enhanced Host Controller Interface Specification for Universal Serial Bus, Revision 1.0, it
implements a waking mechanism like the one in the example. The amount of time that the ADE
“sleeps” is 10 µs ± 30 ns.
Write Policies for Asynchronous DMA
The Asynchronous DMA engine performs writes for the following reasons:
NOTES:
Data Encoding and Bit Stuffing
See Chapter 8 of the Universal Serial Bus Specification, Revision 2.0.
Packet Formats
See Chapter 8 of the Universal Serial Bus Specification, Revision 2.0.
1. The Asynchronous DMA Engine (ADE) will only generate writes after a transaction is executed on USB.
2. Status writes are always performed after In Data writes for the same transaction.
Asynchronous Queue
Head Overlay
Asynchronous Queue
Head Status Write
Asynchronous qTD
Status Write
In Data
Memory Structure
Up to 1297
(DWords)
Size
14
34
3
Only the 64-bit addressing format is supported. DWords 0C:43h are
written.
DWords 14:1Fh are written.
DWords 04:0Fh are written. PID Code, IOC, Buffer Pointer (Page 0),
and Alt. Next qTD Pointers are re-written with the original value.
The Intel
chunks.
®
ICH5 breaks data writes down into 16-DWord aligned
Comments
Functional Description
219