Specifications

100 Intel
®
Atom™ processor CE4100 Ref# 420826
Platform Design Guide
Intel Confidential
Figure 8-9. GBE Interface Clock Signal Design Example
Intel® Atom™ processor CE4100
RGMII PHY
(RTL8211b)
25MHz
GBE_REFCLK
1000/100/10
125/25/2.5MHz
125MHz
RGMII: Strapping must be set to use
external clock mode
GBE_TXCLK
RGMII
Intel® Atom™ processor CE4100
RMII PHY
(RTL8201n)
25MHz
GBE_REFCLK
50MHz
Not Used
GBE_TXCLK
RMII
RMII: Strapping is set as internal clock
mode
Note: The Intel
®
Atom™ processor CE4100 can provide a 50-MHz clock source to RMII PHY
by GBE_TXCLK signal. However, for RGMII PHY support, the Intel
®
Atom™ processor
CE4100 must obtain an external 125-MHz clock source via GBE_REFCLK
Figure 8-10. GBE TX Interface (except GBE_TXCLK)
Figure 8-11. GBE_TXCLK