Datasheet

Data-Mover Port Interface

SGLS139B − October 2003 − Revised April 2004TSB12LV32-EP

5.1.2.2 Isochronous Packet Transmit Without Automatic Header Insertion

In this mode, both the packet header and data payload is loaded through the data-mover port. This mode is

sometimes called isochronous packet transmit with manual header insertion. This is because the header

quadlet is not preloaded into the header0 register via the microcontroller interface. Instead, it is inserted

manually into the data stream at the same time as the rest of the packet. The following steps further illustrate

the process.

Step 1: Isochronous header information (only one header quadlet in this case) is fetched into the header0

Step 2: Header quadlet is forwarded to the transmitter of the link core.

Step 3: Packet data (payload only) is transmitted through the data mover directly to the transmitter of the link

core.

Step 4: Isochronous packet is sent to the 1394 bus through the Phy.

CFR REGISTER

Step 4

Data-

Mover

Port

Header0 Register at 38h

LINK CORE

Transmitter

Receiver

Step 2

Step 3 (Packet Data)

Packet Sent to 1394 Bus

Through the Phy

Step 1 (Header Fetched)

Step 1

(Header Supplied)

Step 3

(Packet Data)

Figure 5−8. Isochronous Transmit Without Auto Header Insertion