Serial Interfaces
PHYTEC Messtechnik GmbH 2005 L-645e_1
47
8
Serial Interfaces
8.1
RS-232 Interface
A dual-channel RS-232 transceiver is located on the
phyCORE-MCF548x at U12. This device adjusts the signal levels of
the TXD0_TTL/RXD0_TTL and TXD1_TTL/RXD1_TTL lines
(MCF548X UART). The RS-232 interface enables connection of the
module to a COM port on a host-PC or other peripheral devices. In
this instance, the RXD0 or RXD1 line (X2D22/X2C21) of the
transceiver is connected to the corresponding TXD line of the COM
port; while the TXD0 or TXD1 line (X2D23/X2C23) is connected to
the RXD line of the COM port. The Ground circuitry of the
phyCORE-MCF548x must also be connected to the applicable Ground
pin on the COM port.
The micrcontroller’s on-chip UART supports handshake signal
communication. Use of an RS-232 signal level in support of
handshake communication requires use of an external
RS-232 transceiver not located on the module.
Furthermore it is possible to use the TTL signals of both of the UART
channels externally. These signals are available at X2D16, X2D17
(RXD0_TTL, TXD0_TTL) and X2C19, X2C20 (RXD1_TTL,
TXD1_TTL) on the phyCORE-connector. External connection of TTL
signals is required for galvanic separation of the interface signals.
Using the solder jumpers J12 and J13, the TTL transceiver outputs of
the on-board RS-232 transceiver devices can be disconnected from the
receive lines RXD0_TTL and RXD1_TTL. This is required so that the
external transceiver does not drive signals against the on-board
transceiver. The transmit lines TXD0_TTL / TXD1_TTL can be
connected parallel to the transceiver input without causing any signal
conflicts.
Summary of Contents for phyCORE-MCF548x
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