PXF4333 Datasheet, PDF (165/361 Pages) Infineon Technologies AG – ABM 3G ATM Buf fer Manager

ABM-3G
PXF 4333 V1.1
Register Description
Register 8 UA5TXCMD/DA5TXCMD
Upstream/Downstream AAL5 Transmit Command Registers
•
CPU Accessibility:
Reset Value:
Offset Address:
Typical Usage:
Read/Write
0000_H
UA5TXCMD 0A_H
DA5TXCMD 1A_H
Written by CPU (write only, read always returns 0000)
Bit
15
14
13
12
11
10
9
8
AAL5EN
PLENGTH(14:8)
Bit
7
6
5
4
3
2
1
0
PLENGTH(7:0)
•
AAL5EN
PLENGTH(14:0)
AAL5 Segmentation Enable
This bit enables AAL5 segmentation process accompanied by the
payload length octet counter PLENGTH:
’0’
AAL5 segmentation is disabled. Payload data octets
written to the cell transmit data registers are ignored.
Note: Setting AAL5EN=’0’ during an active packet
segmentation process leads to an abort of the
packet, i.e. the current cell is inserted with
PT(0)=’1’ (End of Packet indication) and CPCS-
SDU Length field of the trailer set to 0.
To abort it is recommended to write all 0 to the
register: AAL5EN | PLENGTH(14:0) = 0000_H
’1’
AAL5 segmentation is enabled. Payload data octets
written to the cell transmit data registers are processed
and the CPCS-PDU trailer is automatically appended in
the last cell controlled by the payload length octet
counter.
Payload Length Octet Counter
This bit field represents the number of PDU payload octets for the
current packet and is equal to the CPCS-SDU length field which is
automatically inserted in the PDU trailer (last cell of the packet).
The ABM-3G uses this counter value to control the AAL5
segmentation process.
Note: The maximum supported CPCS-SDU length is 32767 octets.
Data Sheet
165
2001-12-17