Functional Description
5.18.1
5.18.2
5.18.3
Data Structures in Main Memory
Section 3.1 - 3.3 of the Universal Host Controller Interface Specification, Revision 1.1
details the data structures used to communicate control, status, and data between
software and the ICH10.
Data Transfers to/from Main Memory
Section 3.4 of the Universal Host Controller Interface Specification, Revision 1.1
describes the details on how HCD and the ICH10 communicate via the Schedule data
structures.
Data Encoding and Bit Stuffing
The ICH10 USB employs NRZI data encoding (Non-Return to Zero Inverted) when
transmitting packets. Full details on this implementation are given in the Universal
Serial Bus Specification, Revision 2.0.
5.18.4
Bus Protocol
5.18.4.1
Bit Ordering
Bits are sent out onto the bus least significant bit (LSb) first, followed by next LSb,
through to the most significant bit (MSb) last.
5.18.4.2
SYNC Field
All packets begin with a synchronization (SYNC) field, which is a coded sequence that
generates a maximum edge transition density. The SYNC field appears on the bus as
IDLE followed by the binary string “KJKJKJKK,” in its NRZI encoding. It is used by the
input circuitry to align incoming data with the local clock and is defined to be 8 bits in
length. SYNC serves only as a synchronization mechanism. The last two bits in the
SYNC field are a marker that is used to identify the first bit of the PID. All subsequent
bits in the packet must be indexed from this point.
5.18.4.3
5.18.4.4
Packet Field Formats
All packets have distinct start and end of packet delimiters. Full details are given in the
Universal Serial Bus Specification, Revision 2.0, in Section 8.3.1.
Address Fields
Function endpoints are addressed using the function address field and the endpoint
field. Full details on this are given in the Universal Serial Bus Specification, Revision
2.0, in Section 8.3.2.
5.18.4.5
5.18.4.6
Frame Number Field
The frame number field is an 11-bit field that is incremented by the host on a per frame
basis. The frame number field rolls over upon reaching its maximum value of 7FFh, and
is sent only for SOF tokens at the start of each frame.
Data Field
The data field may range from 0 to 1023 bytes and must be an integral numbers of
bytes. Data bits within each byte are shifted out LSB first.
Datasheet
193
INTEL [ INTEL ]
