VSC7511 datasheet(110/324 Pages) MICROSEMI

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Functional Descriptions

VMDS-10488 VSC7511 Datasheet Revision 4.2

Each VCAP has defined various constants and are accessed using the registers listed in the following

table.

Figure 28 •

VCAP Configuration Overview

A TCAM entry consists of entry data, an entry mask, and a type-group value. The type-group value is

used internally to differentiate between VCAP lookups of different subword sizes. Each TCAM entry has

an associated action entry. In addition, the action RAM has an entry for each of the default actions in the

VCAP. The entries in the action RAM consists of action data and a counter value.

For a write access, the TCAM and action entry must be written to the cache and then copied from the

cache to the TCAM/RAM. For a read access, the TCAM and action entry must first be retrieved from the

TCAM/RAM before being read from the cache. When a read or write operation is initiated, it is possible to

individually select if the operation should be applied to the TCAM and/or action RAM. When data is

moved between the cache and the TCAM/RAM, it is always the entire entry that is moved. For VCAPs

with several subwords per entry, this must be taken into account if only a single subword of a TCAM entry

should be updated. To modify a single subword, the entire TCAM entry must be read, then the subword

must be modified in the cache, and finally the entry must be written back to the TCAM.

The cache can hold only one VCAP entry (TCAM and action entry) at a time. After the TCAM and action

entry are written to the cache, the cache must be copied to the TCAM and RAM before new entries can

be written to the cache.

VCAP_STICKY

Sticky-bit indications

None

Table 68 •

VCAP Constants

Description

Replication

ENTRY_WIDTH

Width of entry field

None

ENTRY_CNT

Number of entries

None

ENTRY_SWCNT

Number of subwords

None

ENTRY_TG_WIDTH

Width of type-group field

None

ACTION_DEF_CNT

Number of default actions

None

ACTION_WIDTH

Width of action field

None

CNT_WIDTH

Width of counter field

None

Table 67 •

VCAP Configuration Registers (continued)

Description

Replication

CACHE

Entry

Entry mask

Action

Counter

Type-Group

TCAM

TCAM entry

Action RAM

Action entry

RD/WR/MV

operations

RD/WR

access

to cache

Access

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