IEI Integration ICE-DB-T6 - Manual (Page 63)

Type 6 Carrier Board Design Guide
Page 53
3.8.1.2 Digital and Analog Signals Isolation
Analog audio signals and other digital signals should be routed as far as possible from
each other. All audio circuits require careful PCB layout and grounding to avoid picking up
digital noise on audio-signal lines.
3.8.1.3 EMI Consideration
No signal should cross the split/gap between the ground planes, which would cause a
ground loop, thereby greatly increasing EMI emissions and degrading the analog and
digital signal quality. That is, any signals entering or leaving the analog area must cross
the ground split in the area where the analog ground is attached to the main motherboard
ground.
3.9 LAN (Local Area Network)
All COM Express modules provide at least one Gigabit Ethernet port compliant to the
IEEE 802.3ab specification.
The LAN interface of the COM Express module consists of four pairs of low voltage
differential pair signals designated from 'GBE0_MDI0' (+ and -) to 'GBE0_MDI3' (+ and -)
plus additional control signals for link activity indicators. These signals can be used to
connect a 10/100/1000BaseT RJ-45 connector with integrated or external isolation
magnetics to the carrier board. The corresponding LAN differential pair and control signals
can be found on the modules connector rows A and B.
3.9.1 Signal Description
Table 3-17 shows COM Express Ethernet signals, including pin number, signals, I/O,
power plane, terminal resistors, damping resistors and descriptions.
Pin Signal I/O Description
A13
A12 GBE0_MDI0+
GBE0_MDI0-
I/O
Media Dependent Interface (MDI) differential pair
0. The MDI can operate in 1000, 100, and
10Mbit/sec modes.
A10
A9 GBE0_MDI1+
GBE0_MDI1-
I/O
Media Dependent Interface (MDI) differential pair
1. The MDI can operate in 1000, 100, and
10Mbit/sec modes.
A7
A6 GBE0_MDI2+
GBE0_MDI2-
I/O
Media Dependent Interface (MDI) differential pair
2. The MDI can operate in 1000, 100, and