FW82801EB Intel, FW82801EB Datasheet - Page 205

• Manufacturer Part Number: FW82801EB
• Manufacturer: Intel

Specifications of FW82801EB

• Lead Free Status / RoHS Status: Not Compliant

5.19.4.3
Intel
®
Table 92. PID Format
Table 93. PID Types
82801EB ICH5 / 82801ER ICH5R Datasheet
Packet Field Formats
Field formats for the token, data, and handshake packets are described in the following section. The
effects of NRZI coding and bit stuffing have been removed for the sake of clarity. All packets have
distinct start and end of packet delimiters.
Packet Identifier Field
A packet identifier (PID) immediately follows the SYNC field of every USB packet. A PID
consists of a four bit packet type field followed by a four-bit check field as shown in
PID indicates the type of packet and, by inference, the format of the packet and the type of error
detection applied to the packet. The four-bit check field of the PID insures reliable decoding of the
PID so that the remainder of the packet is interpreted correctly. The PID check field is generated by
performing a 1s complement of the packet type field.
Any PID received with a failed check field or which decodes to a non-defined value is assumed to
be corrupted and the remainder of the packet is assumed to be corrupted and is ignored by the
receiver. PID types, codes, and descriptions are listed in
PIDs are divided into four coding groups: token, data, handshake, and special, with the first two
transmitted PID bits (PID[1:0]) indicating which group. This accounts for the distribution of PID
codes.
Token
Data
Handshake
Special
PID Type
Bit
0
1
2
3
PID Name
SETUP
DATA0
DATA1
STALL
Data Sent
OUT
SOF
ACK
NAK
PRE
IN
PID 0
PID 1
PID 2
PID 3
PID[3:0]
b0001
b1001
b0101
b1101
b0011
b1011
b0010
b1010
b1100
b1110
Bit
4
5
6
7
Address + endpoint number in host -> function transaction
Address + endpoint number in function -> host transaction
Start of frame marker and frame number
Address + endpoint number in host -> function transaction for
setup to a control endpoint
Data packet PID even
Data packet PID odd
Receiver accepts error free data packet
Rx device cannot accept data or Tx device cannot send data
Endpoint is stalled
Host-issued preamble. Enables downstream bus traffic to
low speed devices.
NOT(PID 0)
NOT(PID 1)
NOT(PID 2)
NOT(PID 3)
Data Sent
Table
93.
Description
Functional Description
Table
92. The
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