Z-World RabbitCore RCM3200, Руководство пользователя

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12 RabbitCore RCM3200
2.2 Serial Communication
The RCM3200 board does not have an RS-232 or an RS-485 transceiver directly on the
board. However, an RS-232 or RS-485 interface may be incorporated on the board the
RCM3200 is mounted on. For example, the Prototyping Board has a standard RS-232
transceiver chip.
2.2.1 Serial Ports
There are six serial ports designated as Serial Ports A, B, C, D, E, and F. All six serial
ports can operate in an asynchronous mode up to the baud rate of the system clock divided
by 8. An asynchronous port can handle 7 or 8 data bits. A 9th bit address scheme, where
an additional bit is sent to mark the first byte of a message, is also supported. Serial Ports
A, B, C, and D can also be operated in the clocked serial mode. In this mode, a clock line
synchronously clocks the data in or out. Either of the two communicating devices can sup-
ply the clock.
Serial Ports E and F can also be configured as SDLC/HDLC serial ports. The IrDA proto-
col is also supported in SDLC format by these two ports.
2.2.2 Ethernet Port
Figure 4 shows the pinout for the RJ-45 Ethernet port (J4). Note that some Ethernet con-
nectors are numbered in reverse to the order used here.
Figure 4. RJ-45 Ethernet Port Pinout
Three LEDs are placed next to the RJ-45 Ethernet
jack, one to indicate an Ethernet link (
LNK ), one to
indicate Ethernet activity ( ACT ), and one to indi-
cate when the RCM3200 is connected to a function-
ing 100Base-T network (
SPD ).
The transformer/connector assembly ground is con-
nected to the RCM3200 printed circuit board digital
ground via a 0
Ω
resistor, R42, as shown in Figure 5.
The RJ-45 connector is shielded to minimize EMI
effects to/from the Ethernet signals.
ETHERNET
RJ-45 Plug
1. E_Tx+
2. E_Tx–
3. E_Rx+
6. E_Rx–
1
8
RJ-45 Jack
Figure 5. Isolation Resistor R42
RJ-45 Ethernet Plug
R42
Chassis
Ground
Board
Ground