CN8237EBGB Mindspeed Technologies, CN8237EBGB Datasheet - Page 113

• Manufacturer Part Number: CN8237EBGB
• Description: ATM SAR 622Mbps 3.3V ABR/CBR/GFR/UBR/VBR 456-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8237EBGB

• Package: 456BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 622 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3.135 V

CN8237
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
Figure 5-4. Programmable Block Size Alternate Direct Index Method
Table 5-1. Programmable Block Size Values for Direct Index Lookup
28237-DSH-001-C
VCI_IT_BLK_SZ
Base Register (16)
Value of
000
001
010
011
100
101
110
5.2.2.2 Setup
VPI
Value
of
x
0
1
2
3
4
5
6
VPI Index Table
VCI_IT_PNTR
Figure 5-4
values for the number of VCI Index table and VCC table entries per VCI.
At system initialization, the user configures the CN8237 to comply with either
the 8-bit UNI VPI field or the 12-bit NNI VPI field, by setting the RSM_CTRL0
(VPI_MASK) bit to a logic high for UNI operation or a logic low for NNI
operation. This configuration determines whether the CN8237 will treat the upper
nibble of the first header octet of each received cell as the GFC field (in the UNI
VPI definition), or as an extension of the VPI address. This gives an address
range for VPIs of either 256 entries (for UNI) or 4096 entries (for NNI). This sets
the VPI Index table size and dictates the number of VCI Index tables to be
allocated.
Portion of Cell’s
VCI Index Table
The data structures that facilitate this scheme are illustrated in
Table 5-1
VCI[15:0]
VCI[15:1]
VCI[15:2]
VCI[15:3]
VCI[15:4]
VCI[15:5]
VCI[15:6]
VCI
Mindspeed Technologies
illustrates the alternate lookup mechanism.
VCI [15:x]
shows the relationships of the values in VCI_IT_BLK_SZ, and the
Possible VCI Index
Table Entries per
Number of
VCC_BLOCK_INDEX
65536
32768
16384
VCI Index Table
8192
4096
2048
1024
VPI
(For one VPI)
™
Where x = value of VCI_IT_BLK_SZ
Portion of Cell’s
(No pointer)
VCC Table
VCI[1:0]
VCI[2:0]
VCI[3:0]
VCI[4:0]
VCI[5:0]
5.2 Reassembly Functional Description
VCI[0]
is not applicable)
(For x=0, pointer
VCI
VCI [x-1:0]
5.0 Reassembly Coprocessor
Index Table Entry
Entries per VCI
Possible VCC
Reassembly
VCC Table
Number of
Section
16
32
64
1
2
4
8
5.7.1.
8237_040
5-5