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i.MX8M SMARC SOM Hardware User Guide
iWave Systems Technologies Pvt. Ltd.
2.7.1
Gigabit Ethernet
The i.MX8M SMARC SOM supports two Gigabit Ethernet using one on SOM Ethernet PHY
“
AR8031
” from
Atheros,
Qualcomm
and one from PCIe to Ethernet controller “
RTL8119I
” from Realtek.
ENET of i.MX8M are connected to
AR8031 to support GBE0 port of SMARC edge connector and PCIe_2 is connected to RTL8119I to support GBE1 port of
SMARC edge connector.
The AR8031 integrates Atheros Green ETHOS® power saving technologies and significantly saves power not only during
the work time, but also overtime. Atheros Green ETHOS® power savings include ultra-low power in cable unplugged
mode or port power down mode, and automatic optimized power saving based on cable length. The AR8031 also
supports IEEE 802.3az EEE standard (Energy Efficient Ethernet) and Atheros proprietary SmartEEE. SmartEEE allows
legacy MAC/SoC devices without 802.3az support to function as a complete 802.3az system. Further, the AR8031
supports Wake-on-LAN (WoL) feature to be able to help manage and regulate total system power requirements.
The Realtek RTL8119I 10/100/1000M Ethernet Controller combines a triple-speed IEEE 802.3 compliant Media Access
Controller (MAC) with a triple-speed Ethernet transceiver, PCIe bus controller and embedded memory. With state-of-
the-art DSP technology and mixed-mode signal technology, the RTL8119I offer high speed transmission over CAT5 UTP
cable or CAT3 UTP (10Mbps only) cable. Functions such as crossover detection and Auto-correction, polarity
correction, adaptive equalization, cross-talk cancellation, echo cancellation, timing recovery and error correctio are
implemented to provide robust transmission and reception capability at high speed.
For more details on GBE0 pinouts, refer below Table:
SMARC
Pin No.
SMARC Edge Signal
Name
CPU Ball Name/
Pin Number
Signal Type/
Termination
Description
P19
GBE0_MDI3-
NA
IO, GBE
Gigabit Ethernet MDI differential pair 3
negative.
P20
GB
NA
IO, GBE
Gigabit Ethernet MDI differential pair 3
positive.
P21
GBE0_LINK100#
NA
O, 3.3V CMOS
100Mbps Ethernet link status LED
Note: Connect to Cathode of LED.
P22
GBE0_LINK1000#
NA
O, 3.3V CMOS
68K PD
Gigabit Ethernet link status LED
Note: Connect to Cathode of LED.
P23
GBE0_MDI2-
NA
IO, GBE
Gigabit Ethernet MDI differential pair 2
negative.
P24
GB
NA
IO, GBE
Gigabit Ethernet MDI differential pair 2
positive.
P25
GBE0_LINK_ACT#
NA
O, 3.3V CMOS
68K PD
Gigabit Ethernet activity status
Note: Connect to Cathode of LED.
P26
GBE0_MDI1-
NA
IO, GBE
Gigabit Ethernet MDI differential pair 1
negative.