Datasheet

4–5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
spd tLabel rt tCode priority
destinationID rCode
RESERVED
dataLength extended_tCode
block data
Reserved
Reserved
Figure 4–8. Block-Transmit Format (Write Response)
Table 4–2. Block-Transmit Format Functions
FIELD NAME DESCRIPTION
spd The spd field indicates the speed at which the current packet is to be sent (00 = 100 Mbits/s,
01 = 200 Mbits/s, and 10 = 400 Mbits/s, and 11 is undefined).
tLabel 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.
rt The rt field is the retry code for the current packet is: 00 = new, 01 = retry_X, 10 = retryA, and
11 = retryB.
tCode The tCode field is the transaction code for the current packet (see Table 6–10 of IEEE
1394
-1995 standard).
priority 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
-1995 standard).
destinationID The destinationID field is the concatenation of the 10-bit bus number and the 6-bit node
number that forms the destination node address of the current packet.
rCode
Specifies the result of the read request transaction. The response codes that may be returned
to the requesting agent are defined as follows:
Response
Code
Name Description
0 resp_complete Node successfully completed requested operation.
1–3 Reserved
4 resp_conflict_error Resource conflict detected by responding agent.
Request may be retried.
5 resp_data_error Hardware error. Data not available.
6 resp_type_error Field within request packet header contains
unsupported or invalid value.
7 resp_address_error Address location within specified node not accessible.
8 – Fh Reserved
destination OffsetHigh,
destination OffsetLow
The concatenation of these two fields addresses a quadlet in the destination node address
space. This address must be quadlet aligned (modulo 4).
dataLength The dataLength field contains the number of data bytes to be transmitted in the packet.
extended_tcode The block extended_tCode to be performed on the data in the current packet (see Table 6–11
of the IEEE 1394
-1995 standard).
block data The block data field contains the data to be sent. If dataLength is 0, no data should be written
into the FIFO for this field. Regardless of the destination or source alignment of the data, the
first byte of the block must appear in byte 0 of the first quadlet.