Multi-Service Access Device For Channelized Interfaces
Telecom Standard Product Data Sheet
Production
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990823, Issue 4
580
The Block Pointer – this is calculated using the starting Block number, which should be an
integral multiple of the FIFO size. Since there are 192 Blocks in a Bank, the starting Block
number is actually an 8 bit number. However, since the smallest FIFO is a multiple of 8 Blocks,
only the upper 5 are significant – these 5 bits are called the Block Pointer. The Block Pointer is
specified in the FIFO Indirect Configuration register in the BLOCK_PTR[4:0] field.
The FIFO Size – this is a 2 bit number that specifies one of 3 possible sizes for the FIFO. Refer to
Table 54 for the values used to specify the FIFO sizes, and a guide to sizing the FIFO based on
the bandwidth of the associated PHY. It is up to the discretion of the user to apply this guide to
each specific case. This number is specified in the FIFO Indirect Configuration register in the
FIFO_BS[1:0] field.
A FIFO occupies the number of Blocks specified by it’s size starting at the Block Pointer. The
user must not configure the Block pointers such that two FIFOs overlap. The user can, however,
have gaps between consecutive Blocks, which can potentially be filled by expanding one or the
other Block. However, since only 3 FIFO sizes are valid, the user cannot arbitrarily expand a
FIFO. Care must be taken to ensure that when expanding from one size to the next, the FIFOs do
not overlap. Refer to Section 14.14 for a guide to expanding and contracting configured Blocks
in the SDQ.
The following table illustrates the configuration for a typical case. This case involves 3 PHYs
that have a bandwidth of STS-12, and are allocated 192 Block FIFOs each. There is one STS-3c
PHY configured, using a 48 Block FIFO, 6 STS-1 FIFOs each with a 16 Block FIFO, and 3 DS3
PHYs, each with 16 Block FIFOs. Bank 0, Bank 1 and Bank 3 have one FIFO each, while Bank
2 has 10 FIFOs. The sum of all the Blocks used in this example is 768 which is the maximum
number of Blocks available. The rest of the configuration is according to the table.
Table 56 SDQ Configuration Example
UL3/PL3
Channel #
PHYID
[5:0]
BW
Size
(Blocks/
Cells)
FIFO_BS
[1:0]
Bank
FIFO_
NUMBER
[5:0]
Starting
Block
BLOCK_
PTR[4:0]
0
0x00
STS-12c
192/48
‘b11
0
0x00
0x0
0x0
12
0x0C
STS-12c
192/48
‘b11
1
0x10
0x0
0x0
24
0x18
STS-3
48/12
‘b10
2
0x20
0x0
0x0
25
0x19
STS-1
16/4
‘b01
2
0x21
0x30
0x6
26
0x1A
STS-1
16/4
‘b01
2
0x22
0x40
0x8
27
0x1B
STS-1
16/4
‘b01
2
0x23
0x50
0xA
28
0x1C
STS-1
16/4
‘b01
2
0x24
0x60
0xC
29
0x1D
STS-1
16/4
‘b01
2
0x25
0x70
0xE
30
0x1E
STS-1
16/4
‘b01
2
0x26
0x80
0x10
31
0x1F
DS3
16/4
‘b01
2
0x27
0x90
0x12
32
0x20
DS3
16/4
‘b01
2
0x28
0xA0
0x14
33
0x21
DS3
16/4
‘b01
2
0x29
0xB0
0x16
36
0x24
STS-3c
16/4
‘b01
3
0x30
0x0
0x0