82801BA Datasheet, PDF (183/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
Table 5-68. PID Types
PID Type
Token
Data
Handshake
Special
PID Name
OUT
IN
SOF
SETUP
DATA0
DATA1
ACK
NAK
STALL
PRE
PID[3:0]
b0001
b1001
b0101
b1101
b0011
b1011
b0010
b1010
b1110
b1100
Description
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.
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.
5.16.4.4 Address Fields
Function endpoints are addressed using two fields: the function address field and the endpoint
field.
Table 5-69. Address Field
Bit
0
1
2
3
Data Sent
ADDR 0
ADDR 1
ADDR 2
ADDR 3
Bit
Data Sent
4
ADDR 4
5
ADDR 5
6
ADDR 6
Address Field
The function address (ADDR) field specifies the function, via its address, that is either the source
or destination of a data packet, depending on the value of the token PID. As shown in Table 5-69, a
total of 128 addresses are specified as ADDR[6:0]. The ADDR field is specified for IN, SETUP,
and OUT tokens.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
5-121