IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 711 / 744

Notes
PES32NT24xG2 User Manual 26 - 1 January 30, 2013
®
Chapter 26
Usage Models
Introduction
This chapter describes possible configurations of the PES32NT24xG2 switch and presents some impor-
tant system usage models. The intent is to document important non-obvious device configuration proce-
dures as well as usage models for the purpose of ensuring design correctness.
For each configuration, a series of steps to configure the device is outlined without necessarily delving
into a detailed description of each step. Detailed descriptions on configuring the device are provided in
other chapters of this document. Configurations other than those described in this chapter are possible.
The PES32NT24xG2 is one member of a family of PCI Express® devices from IDT. In this chapter,
several related devices are used as examples; however, each example is also applicable to the
PES32NT24xG2.
Boot-time Stack Reconfiguration
Goal
Reconfigure the stacks (at boot-time via serial EEPROM) to obtain the following configuration:
– One x8 port
– Sixteen x1 ports
Assumptions
– PES24NT24AG2 switch device.
– The switch boots in switch mode “Single partition with Serial EEPROM initialization”.
– Upstream port: Port 16 (x8)
– Downstream ports: Ports 0 to 15 (x1)
Figure 26.1 shows the configuration.
Figure 26.1 PES24NT24AG2 with One x8 port and Sixteen x1 Ports
Description
Stacks 0 and 1 will operate with four x1 ports each. In this product option, these stacks operate in this
mode automatically and the stack configuration can’t be modified (i.e., the ports in the stacks are non-
mergeable). Stack 2 will operate with eight x1 ports. To achieve this configuration, the STK2CFG[4:0] pins
of the device can be tied to 0x1B on the system board.
PES24NT24AG2
Serial
EEPROM
x8
x1
P16
P0 P1 P15
x1