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CHAPTER 5 SAR FUNCTION
167
5.4.7 Issuing a Transmit Indication
The
μ
PD98405 writes a transmit indication into a mailbox for each packet descriptor. The mailbox used for
transmission is mailbox 2 or 3, which stores the indication to either of the mailboxes according to the "MB" bits
of the packet descriptor set by the host. For a packet for which the transmit indication is masked (while the IM
bit of the packet descriptor is 1), however, neither a transmit indication nor an interrupt is issued.
The
μ
PD98405 executes writing of the transmit indication once all the data in a packet has been read. Note
that even if the transmission indication has been issued, it does not indicate that transmission to the PHY layer
device of that packet has been completed.
The
μ
PD98405 also issues a transmit indication when a Deactivate_Channel command is issued during
packet transmission. Even when a packet for which transmit indication is masked is being transmitted, the
μ
PD98405 issues a transmit indication if transmission is interrupted by the execution of a Deactivate_Channel
command.
When the transmit indication is stored, the
μ
PD98405 sets the corresponding MM bit of the GSR register to
1, and, provided it is not masked, issues an interrupt.
Caution
A transmit indication is issued for each packet for all data of both AAL-5 and non-AAL-5
packets (OAM F5 and raw cell transmission packets), unlike a receive indication.
For an explanation of the contents and processing of the indication, see
Section 5.6
.
The
μ
PD98405 supports the following three types of transmission, which can be selected using a packet
descriptor:
Table 5-4. Data Supported by the
μ
PD98405 Transmit Function
Setting
Data length
Indication
AAL-5
trailer
CRC-10
Remarks
AAL-5 data
PTI = "0xx"
AAL = 1
Up to 65,535
bytes
Issued
Automati-
cally
added
Not added Can be
Cannot
be
inserted
Transmission of
other than AAL-5
packet
(raw cell
transmission)
OAM F5 cell
transmission
PTI = "0xx"
AAL = 0
Up to 65,535
bytes (only a
multiple of
48 bytes)
Issued
inserted
The CLPM field cannot be set
to "01."
The least significant bit of the
PTI field is not changed for the
last cell.
The CLPM field cannot be set
to "01."
Only single-buffer mode can
be used.
PTI = "1xx"
AAL = 0
48 bytes
Issued
Not added Can be
inserted