PM3351-SW datasheet(75/268 Pages) PMC

75 / 268 page

PM3351 ELAN 1X100

DATA SHEET

PMC-970113

ISSUE 3

SINGLE PORT FAST ETHERNET SWITCH

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

parameters supplied during the generation of a boot image that control these addresses

is given next to the memory regions. A description of how these addresses may be

computed, as well as a sample memory map for a typical system configuration, is

provided later in this section.

0x000000

Switch Processor Operating Environment

BIGSTRUCTst

Packet Buffers

DDRINGst

Transfer rings

DISPSTRUCTst

Message Data Descriptors

HASHSTRUCTst

Hash Buckets

SMALLSTRUCTst

Forwarding Tags

BOOT_START

Boot Image Copy Area

Top of RAM

Switch Processor Operating Environment

The Switch Processor requires a small operating environment (i.e., data structures and

variables) for performing basic frame switching functions. This environment is set up in

the external RAM during the bootstrap initialization and configuration phase. The entire

operating environment occupies about 43 kbytes of space, and must be located starting

at address 0x000000 hex in the external memory. The operating environment excludes

the space used by Ethernet frame buffers and the queueing structures used to track

them, and also does not include the code, data or stack spaces that are needed by the

(optional) RTOS, UDP/IP stack, or SNMP agent firmware. The general layout of the

operating environment is as follows:

PM3351-SW Datasheet(PDF) 75 Page - PMC-Sierra, Inc