
PMC-Sierra, Inc.
PM73488 QSE
L
PMC-980616
Issue 3
5 Gbit/s ATMSwitch Fabric Element
Released
Datasheet
109
9.3.28
CELL_START_OFFSET
Address: 86
h
Type: Read/Write
Format: Refer to the following table.
9.3.29
BP_CONTROL_REGISTER
Address: 87
h
Type: Read/Write
Format: Refer to the following table.
Note: The BP_CONTROL_REGISTER is typically used for fine-tuning multicast performance. For ini-
tial system bring-up, this register may be left at the power-up default value.
9.3.30
ACK_PAYLOAD
Address: 88
h
Type: Read/Write
Format: Refer to the following table.
Field (Bits)
Description
Not used
(7)
Write with a 0 to maintain future software compatibility.
(6:0)
Offset between (external) CELL_START and Local CELL_START (NOTE:
The CSTART offset must only be changed when the device is in
software reset.
) Legal values for this register are between 0 and 117.
Field (Bits)
Description
Not used
(7:4)
Write with a 0 to maintain future software compatibility.
GLOBAL_LIMIT_2
(3)
If 1, second port threshold is off.
GLOBAL_LIMIT_1
(2)
If 1, first port threshold is off.
PER_PORT_LIMIT
(1)
1
0
Each port allowed to have a maximum of 4 cells pending.
Each port allowed to have a maximum of 3 cells pending.
EARLY_BP
(0)
1
0
Early (hence conservative) backpressure.
Optimal backpressure.
Field (Bits)
Description
PARITY_NACK
(7:4)
ACK Payload for Parity Error Cells.
Reset to 8
h
(Default is ONACK).