Freescale Semiconductor M5211DEMO, Руководство пользователя

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Communications
Demonstration Board for Freescale MCF5211, Rev. 1
Freescale Semiconductor 13
11 Communications
The M5211DEMO board provides two Serial Communications Interface (SCI) ports, one Serial Peripheral
Interface (SPI) port, and one Inter-Integrated Controller (IIC) port. RS-232 communications are supported
through a DB9 connector and connector J1. SPI and IIC communications are supported through connector
J1. The COM_EN option header enables SCI0 operation on the board.
11.1 SCI Port
An RS-232 transceiver provides RS-232 to TTL/CMOS logic-level translation between the COM
connector and the MCU. The COM connector is a 9-pin Dsub, right-angle connector. A ferrite bead on
shield ground provides conducted immunity protection. Communication signals TXD0 and RXD0 are
routed from the transceiver to the MCU. These signals are also available on connector J1. Hardware flow
control signals RTS0 and CTS0are also routed from the transceiver to the MCU.
Serial communications signals RXD1, TXD1, RTS1, and CTS1 are available on connector J1 and route
directly between the MCU and connector J1. The SCI1 port does not have a RS-232 logic-level translation.
11.2 COM_EN
The COM_EN option header ( Figure 9 ) individually connects and disconnects SCI0 signals between the
MCU and the SCI transceiver. Removing a shunt disconnects the associated signal. Installing a shunt
connects the associated signal.
Figure 9. COM_EN Option Header
11.2.1 COM Connector
A standard 9-pin Dsub connector provides external connections for the SCI0 port. The Dsub shell is
connected to board ground through a ferrite bead. The ferrite bead provides noise isolation on the RS-232
connection. The DB9 connector pinout is shown in
Figure 10 .
Shunt
On Off
Enabled Disabled
Enabled Disabled
Enabled Disabled
Enabled Disabled
CTS
RTS
RXD
TXD
COM_EN