PM5381-BI PMC-Sierra, Inc., PM5381-BI Datasheet - Page 397

• Manufacturer Part Number: PM5381-BI
• Description: ATM UNI, Single Channel ATM PHY Interface for 2488.32Mbps
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2000489, Issue 4
Register 076AH: RXSDQ FIFO Indirect Data Available Threshold
This register is used to set the Data Available Threshold for a FIFO. This threshold is explained in
the Operation section. A FIFO does not need to be enabled to set this threshold. In order to
change this value for a FIFO, the user should first disable it, write in the new value, and enable it
again. See section 13.8: RXSDQ and TXSDQ Data Available and Burst-Size Operation for more
information on configuring the TXSDQ, RXSDQ, TXPHY, and RXPHY. This register must be
accessed via an indirect register read or write via register 0768H. See also section 13.19:
Accessing Indirect Registers.
All Reserved bits must be set to their default values for proper operation.
DT[7:0]
Bit
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
These bits specify the Data Available threshold for the FIFO selected by the RXSDQ FIFO
Indirect Address register’s PHYID[5:0] bits. When this threshold is being set, these bits are
written to by the user, and when this threshold is being read, these bits hold the previously
configured data. The threshold is equal to DT[7:0] + 1.
This threshold is set in 16 byte Blocks. This threshold can never be greater than the size of
the FIFO. The absolute maximum value is DT[7:0] +1 = 16. This number should be a
standard fraction of the FIFO size in blocks. In the case of ATM FIFOs, this number should
be set to a value of DT[7:0] = 3 (ATM cells are 4 Blocks long). Note that the RXPHY
BURST_SIZE[3:0] value must be less than or equal to DT.
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
DT[7]
DT[6]
DT[5]
DT[4]
DT[3]
DT[2]
DT[1]
DT[0]
Reserved
Reserved
Reserved
Reserved
Reserved
Function
Unused
Unused
Unused
S/UNI-2488 Telecom Standard Product Datasheet
Default
0
0
0
0
0
0
1
1
X
X
X
0
0
0
1
1
Released
397