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S/UNI-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
369
Register 0x2C4: Bypass SDQ Indirect Address
Writing to this register initiates a read or write access (based on RWB) to a set of indirect
registers that set up the FIFOs for each PHY: Bypass SDQ Indirect Configuration, Bypass SDQ
Buffer and Data Available Threshold and Bypass SDQ Indirect Cell Count. FIFOs must be
configured according to a set of rules defined in Section 13.1. In order to change the current
setup of a FIFO, it is recommended that the user read the existing setup information first, makes
any modifications as required, and write back the new configuration .
Bit
Type
Function
Default
31:16
Unused
X
15
R
BUSY
0
14
R/W
RWB
1
13
R/W
FLUSH
1
12
R
EMPTY
1
11:6
Unused
X
5:0
R/W
PHYID[5:0]
0
PHYID[5:0]
This is a 6-bit number that is used to describe the current FIFO being addressed by the
Bypass SDQ FIFO Indirect Configuration and the Bypass SDQ Cells and Packets Count
Register. The range of FIFO numbers that can be used is 0 to 47.
EMPTY
This read-only bit indicates if the requested FIFO is empty or not. When this bit is read as 1,
the FIFO number specified in PHYID[5:0] in the FIFO Indirect Address register has no data
available to be read out. This bit reflects the read-side perspective and will not react
immediately to writes. Before reconfiguring a disabled FIFO, this bit needs to be sampled at
1, indicating that the FIFO is currently empty. A non-empty FIFO can be forced empty by
writing FLUSH to logic 1.
FLUSH
FLUSH is an indirect configuration register bit. When RWB = 0, the value written to this bit
will be written to the FLUSH bit for the specified PHYID. A logic 1 on FLUSH causes the
SDQ to discard all the current data in the specified FIFO; a logic 0 must be written to the
FIFO in order for it to begin processing data again. FLUSH is typically used when a non-
empty FIFO needs to be reconfigured.