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Datasheet of 20-101-1194 - MODULE RABBITCORE RCM3309 ROHS
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User’s Manual
29
4.2.2 Ethernet Port
Figure 7 shows the pinout for the RJ-45 Ethernet port (J3). Note that some Ethernet con-
nectors are numbered in reverse to the order used here.
Figure 7. RJ-45 Ethernet Port Pinout
The RJ-45 connector is shielded to minimize EMI effects to/from the Ethernet signals.
The Ethernet chip supports auto MDI/MDIX on the Ethernet port to choose the Ethernet
interface automatically based on whether a crossover cable or a straight-through cable is
used in a particular setup. The Ethernet chip may spike the current draw by up to 200 mA
while it is searching to determine the type of Ethernet cable. This search is repeated every
second if no Ethernet cable is detected. If you do not plan to connect an Ethernet cable,
use the Dynamic C
pd_powerdown()
function call to turn off the Ethernet chip. The
pd_powerup()
function call is available to turn the Ethernet chip back on at a later time.
These function calls are described in the
Dynamic C TCP/IP User’s Manual, Volume 1
.
Three LEDs are placed next to the RJ-45 Ethernet
jack, one to indicate Ethernet link/activity (
LNK/
ACT
), one to indicate when the RCM3309/RCM3319
is connected to a functioning 100Base-T network
(
SPD
), and one (
FDX/COL
) to indicate whether the
current connection is in full-duplex mode (steady
on) or that a half-duplex connection is experiencing
collisions (blinks).
The transformer/connector assembly ground is con-
nected to the RCM3209 printed circuit board digital
ground via a ferrite bead, L1, as shown in Figure 8.
Figure 8. Ferrite Bead Isolation
ETHERNET
RJ-45 Plug
1. E_Tx+
2. E_Tx
3. E_Rx+
6. E_Rx
1
8
RJ-45 Jack
RJ-45 Ethernet Jack
L1
Chassis
Ground
Board
Ground
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