![](http://datasheet.mmic.net.cn/390000/TSB42AA4I_datasheet_16839080/TSB42AA4I_72.png)
57
rsv
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
31
destination Offset Low
destination Offset High
destination ID
priority
tCode
rt
tLabel
quadlet data (for write request and read response)
rsv
pad
ackCode
P
S
spd
r
Data Size
source ID
Figure 56. Quadlet Receive Format
Table 58. Quadlet Receive Format Functions
FIELD NAME
Data Size
S
DESCRIPTION
Packet control token Size of the packet in quadlets
Packet control token - This bit is set to 1 whenever the packet control token is attached to a
self-ID packet.
Packet control token - This bit is set to 1 whenever the packet control token is attached to a
PHY packet.
Packet control token - This 5-bit field holds the acknowledge code sent by the receiver for the
current packet. See Table 510 for ACK codes.
Packet control token - Number of padding bytes added
Packet control token - The spd field indicates the speed at which the current packet was sent.
00 = 100 Mbits/s, 01 = 200 Mbits/s, 10 = 400 Mbits/s, and 11 is undefined for this
implementation.
P
ackCode
pad
spd
destination ID
The destinationID field contains the concatenation of the 10-bit bus number and the 6-bit
node number that forms the node address to which the current packet is being sent.
The tLabel field is the transaction label, which is a unique tag for each outstanding
transaction between two nodes. This field is used to pair up a response packet with its
corresponding request packet.
tLabel
rt
The rt field is the retry code for the current packet is 00 = new, 01 = retry_X, 10 = retryA, and
11 = retryB.
The tCode field is the transaction code for the current packet (see Table 610 of the
IEEE-1394 standard).
The priority field contains the priority level for the current packet. For cable implementation,
the value of the bits must be zero (for backplane implementation, see clause 5.4.1.3 and
5.4.2.1 of the IEEE-1394 standard).
tCode
priority
source ID
destination Offset High,
destination Offset Low
The sourceID field contains the node ID of the sender of the current packet.
The concatenation of the destination OffsetHigh and the destination OffsetLow fields
addresses a quadlet in the destination nodes address space. This address must be quadlet
aligned (modulo 4). (The upper four bits of the destination OffsetHigh field are used as the
response code for lock-response packets, and the remaining bits are reserved.)
For write requests and read responses, the quadlet data field holds the transferred data. For
write responses and read requests, this field is not present.
quadlet data