cxd3220r Sony Electronics, cxd3220r Datasheet - Page 55

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

CXD3220R
Mode 2) Page_table_present (p) = 1, Page_size = non-zero, Use page boundary
[Page Table Access]
This mode is used in the case of using the page_table, which is an indirect address table of the SBP-2
protocol. When page_table_present (p) = 1 and page_size = non-zero are set, the ADP enters a transfer mode
using the page_table with the address boundary restriction in effect.
According to the SBP-2 protocol, in the case page_table_present (p) obtained with a normal command block
ORB is equal to "1", since the address of the page_table is indicated in the data_descriptor, it is necessary that
a Block Read request described in section 6.5.1.2 be issued to the address indicated in the data_descriptor,
and that the contents of each page_table (see diagram below) be read. The Block Read response packet is
returned from the initiator and stored in the ARF in the format of a Block Read response (see section 6.5.2.3).
In this mode, there is a page in which segment_offset changes from all "0" to all "1" in the form of a page
boundary. When the lower (page_size + 8) bits of the 1394 serial bus address change to all "1", since this
indicates the end of one page, there is a restriction in which packets cannot be generated that perform data
transmission and reception to an address that goes beyond that page boundary. The number of pages
(number of elements) required for data transfer are indicated in the data_size of the normal command block
ORB. When one page ends, packet transmission and reception is performed again starting at the serial bus
address comprised of segment_base_hi, segment_base_lo and segment_offset of the next element.
Reference: Page table (Example: page_size = 4)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
0
segment_length
segment_base_hi
segment_base_lo
segment_offset
[Data Transfer Using Page Table]
The CXD3220R automatically performs Page Table data transfer for one element. Set segment_length,
segment_base_hi, segment_base_lo and segment_offset written in the page_table of each element obtained
by block reading to xfer_length, segment_base_hi, segment_base_lo and segment_offset of the ADP register
(same register as destination OffsetHigh & destinationOffsetLow). Set the destination_ID obtained from the
data_descriptor in the normal command block ORB for the Destination ID. Set d, spd, max_payload, p and
page_size. ADP transfer starts when the ADPgo bit of the Command register is set to "1".
The ADP sequentially transmits and receives data while generating request packets corresponding to the
data_size represented with max_payload for data of the Page Table corresponding to one element. Data
corresponding to any remaining bytes is transmitted and received with a request packet. The transfer speed of
request packets generated with the ADP is selected between either S100 for spd = 0 or S200 for spd = 1.
The following page indicates a summary of packetizing with respect to this mode.
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