Datasheet

TSB12LV32 Data Formats

SGLS139B − October 2003 − Revised April 2004TSB12LV32-EP

3210 765411109815141312 19181716 20 21 31302928272625242322

spdnumofQuadlets

sourceID

destination OffsetHigh

00 00 0 ackCode 00 0000

prioritytCoderttLabeldestinationID

destination OffsetLow

quadlet data (write requests and read responses only, omitted for write responses and read requests)

Figure 7−4. Data-Mover Quadlet-Receive Format

Table 7−3. Quadlet Receive Format Functions

FIELD NAME DESCRIPTION

numofQuadlets Total number of quadlets in the current packet (payload and header quadlets only).

ackCode This 5-bit field holds the acknowledge code sent by the receiver for the current packet (see Table 6-13 in the draft

standard).

spd The Spd field indicates the speed at which the current packet was sent. 00 = 100 Mbps, 01 = 200 Mbps,

10 = 400 Mbps, and 11 is undefined for this implementation.

destinationID 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.

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).

sourceID The sourceID field contains the node ID of the sender of the current packet.

destination OffsetHigh,

destination OffsetLow

The concatenation of the destination OffsetHigh and the destination OffsetLow fields addresses a quadlet in the

destination node 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.)

quadlet data 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.