82NM10 Datasheet, PDF(175/671 Page) Intel Corporation – Intel® NM10 Family Express Chipset

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82NM10 Datasheet, PDF (175/671 Pages) Intel Corporation – Intel® NM10 Family Express Chipset

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Functional Description

5.18.2

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 Chipset communicate via the Schedule data

structures.

5.18.3

Data Encoding and Bit Stuffing

Chipset 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

5.18.4.1

5.18.4.2

5.18.4.3

5.18.4.4

5.18.4.5

Bus Protocol

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.

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 âKJKJKJKK,â 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 and is not shown in the

following packet diagrams. 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.

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.

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.

Datasheet

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