Table 4.2 Gclk And Pxclk Frequencies When Pxclk Has Ssc; Table 4.3 Port Clocking Mode Requirements; Table 4.4 Valid Pes48H12G2 System Clocking Configurations - Renesas IDT 89HPES48H12G2 User Manual

IDT Clocking
This results in the port clocking mode requirements summarized in Table 4.3.
Based on the requirements outlined in this section, Table 4.4 summarizes valid system clocking configurations (highlighted in green). Invalid
system configurations are highlighted in red.
PES48H12G2 Switch
Port
Port
Clocking
Clock
Mode
Global don't care
Clocked
Global don't care
Clocked
Global don't care
Clocked
Global don't care
Clocked
Local Port PxCLK
Clocked
Local Port PxCLK
Clocked
PES48H12G2 User Manual
Nominal PxCLK
PxCLK SSC
Frequency Modulation
100 MHz + 300ppm +0 / - 5000ppm
100 MHz - 300ppm +0 / - 5000ppm
100 MHz + 300ppm +0 / - 5000ppm
100 MHz - 300ppm +0 / - 5000ppm

Table 4.2 GCLK and PxCLK Frequencies when PxCLK has SSC

Port Clocking Mode
Transmitting and
Global Clocked
Local Port Clocked

Table 4.3 Port Clocking Mode Requirements

Partner
Global
Refclk
Clock
GCLK Same GCLK as the switch
GCLK with Same GCLK as the switch
SSC
GCLK Different Refclk than the
switch
GCLK with Different Refclk than the
SSC switch
GCLK Same PxCLK as the
switch
GCLK with Same PxCLK or different
SSC Refclk as the switch
Table 4.4 Valid PES48H12G2 System Clocking Configurations (Part 1 of 2)
Effective
PxCLK
Frequency
100 Mhz +300 / -
4700ppm
100 Mhz -300 / -
5300ppm
100 Mhz +300 / -
4700ppm
100 Mhz -300 / -
5300ppm
Clock Used by
Global Reference
Port for
Clock Input
Restrictions
Receiving Data
GCLK
PxCLK GCLK must not use SSC
Link
Valid
Config.
Yes Global clocked with common Refclk architecture.
Yes Global clocked with common Refclk architecture and
SSC.
Yes Global clocked with separate Refclk architecture.
No Violates PCI Express +/- 300 ppm clock difference
requirement.
Yes Local port clocked with common Refclk architecture.
No
4 - 3
Allowed
GCLK
Frequency
100 Mhz + / -
300ppm
100 Mhz + / -
300ppm
125 Mhz + / -
300ppm
125 Mhz + / -
300ppm
none
Notes
April 5, 2013