Datasheet
TSB12LV32 Data Formats
70
SGLS139B − October 2003 − Revised April 2004TSB12LV32-EP
Table 7−1. Quadlet Transmit Format Functions
FIELD NAME DESCRIPTION
spd The Spd field indicates the speed at which the current packet is to be sent. 00 = 100 Mbps, 01 = 200 Mbps,
10 = 400 Mbps, and 11 is undefined for this implementation.
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: 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 the 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 clauses 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.
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).
quadlet data For write requests and read responses, the quadlet data field holds the data to be transferred. For write responses and
read requests, this field is not used and should not be written into the FIFO.
rcode
Specifies the result of the read request transaction. The response codes that can be returned to the requesting
agent are defined as follows:
Response
Code
Name Description
0
1−3
4
5
6
7
8-Fh
resp_complete
reserved
resp_conflict_error
resp_data_error
resp_type_error
resp_address_error
reserved
Node successfully completed requested operation
Resource conflict detected by responding agent
Request may be retried.
Hardware error. Data not available
Field within request packet header contains unsupported or invalid value.
Address location within specified node not accessible
7.1.2 Block Transmit
The block-transmit format is shown in Figure 7−2 and is described in Table 7−2. The first quadlet contains
packet-control information. The second and third quadlets contain the 64-bit address for write requests and
read requests and a 4-bit rCode for read responses. The first 16 bits of the fourth quadlet contain the
dataLength field. This is the number of bytes of data in the packet. The remaining 16 bits represent the
extended_tCode field (see Table 6−11 of the IEEE 1394-1995 standard for more information on
extended_tCodes). The block data for a block write request follows the extended_tCode; no block data is
included in a block read request.
3210 765411109815141312 19181716 20 21 31302928272625242322
prioritytCoderttLabelspd
destinationID
dataLength
destination OffsetHigh
destination OffsetLow
block data
extended_tCode
Figure 7−2. Block Transmit Format