cxd3220r Sony Electronics, cxd3220r Datasheet - Page 48

• Manufacturer Part Number: cxd3220r
• Description: Ieee1394 Link/transaction Layer Controller Lsi For Sbp-2
• Manufacturer: Sony Electronics

7-3-2. ADP Sequence (Data Receive)
The following provides an explanation of those ADP functions relating to reception based on the diagram
below.
As is defined in the SBP-2 protocol, data transfer with respect to reception is also initiated by a target.
Therefore, data transfer is performed in the form in which the target (this link IC) reads the initiator memory
using the 1394 Read Block command for the initiator (e.g., host computer). The following illustrates a brief
overview of that sequence.
This is the role of the ADP with regard to reception.
ADP Schematic Diagram
1) First, the CPU initializes the ADP register according to the contents of the ORB obtained.
2) The designated address and 1394 Block Read request command corresponding to the Data_length are
3) Once a bus has been acquired, a Block Read request packet is transmitted to the initiator.
4) After transmission, an Ack code for the Read request packet and a Read response packet containing data
5) The tCode and Transaction Label of packets that are received by the Link Core are checked, and only the
6) The ADP removes the 1394 Header from the received response packet, and automatically stores the
7) Data stored in the ADPRF is output to a peripheral LSI from the transport I/F in synchronization with the
stored in the ADPTF FIFO in accordance with the SBP-2 data transfer format. The stored Read request
packet is then sent to the 1394 Link Core, and the Link Core applies Arbitration to the 1394 bus (via Phy
IC).
corresponding to the Data_length are sent to the target from the initiator.
If this Ack code and Response code are normal, the ADP transmits the next data. In the case of an error,
the status is returned as an error and an interrupt is generated to the CPU.
response packet returned to the ADP is input to the ADP. (Stored in the ADPRF.) Other packets are input
to the ARF.
packet data in the ADPRF.
SDRQ.
ENDEC
Transfer Data to Media
1 LBA
1 LBA
ADPRF
ADPTF
ADP
SBP2 Read Request Packet
Link Request
Link Response
SBP2 Packets
1394 Header
– 48 –
1394 Read Request
1394 Read Response
Core
Link
arbitration &
packet transmit
Read Response
IEEE1394
Serial Bus
CXD3220R