Datasheet
4–1
4 TSB12LV01B Data Formats
The data formats for transmission and reception of data are shown in the following sections. The transmit
format describes the expected organization of data presented to the TSB12LV01B at the host-bus interface.
The receive formats describe the data format that the TSB12LV01B presents to the host-bus interface.
4.1 Asynchronous Transmit (Host Bus to TSB12LV01B)
Asynchronous transmit refers to the use of the asynchronous-transmit FIFO (ATF) interface. There are two
basic formats for data to be transmitted. The first is for quadlet packets, and the second is for block packets.
For transmits, the FIFO address indicates the beginning, middle, and end of a packet. All packet formats
described in this section refer to the way the packets are stored in the internal FIFO memory of the
TSB12LV01B. The host application must conform to the packet formats specified in this section when
accessing the ATF for a write operation and the GRF for a read operation.
4.1.1 Quadlet Transmit
The IEEE 1394-1995 standard specified four types of quadlet transmit packets: write request, read request,
write response, and read response packets. Table 4–1 describes the details of each packet.
4.1.1.1 Quadlet Write-Request and Read-Request Packets
The format for a quadlet write-request packet is shown in Figure 4–1. The first quadlet contains the packet
control information. The second and third quadlets contain the 64-bit, quadlet-aligned destination address.
The fourth quadlet is the quadlet data used. The format for a quadlet read-request packet is shown in
Figure 4–2.
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 destinationOffsetHigh
destinationOffsetLow
quadlet data
Reserved
Figure 4–1. Quadlet-Transmit Format (Write Request)
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 destinationOffsetHigh
destinationOffsetLow
Reserved
Figure 4–2. Quadlet-Transmit Format (Read Request)