Phytec phyCORE-167CR, Hardware Manual

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Serial Interfaces
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PHYTEC Meßtechnik GmbH 2002 L-527e_8
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6 Serial Interfaces
6.1 RS-232 Interface
One RS-232 transceiver is located on the phyCORE-167CR/167CS at
U6. This device converts the signal levels for the P3.11/RxD0 and
P3.10/TxD0 lines, as well as those of the second serial interface,
P3.1/RxD1 and P3.0/TxD1 from TTL level to RS-232 level. Use of
the optional UART on U7 requires changing the jumper settings for
J13 and J14 to 2+3 (refer to section 3.10) in order to route the RxD
and TxD signals to the transceiver. As an alternative, a second
RS-232 interface can be established by software emulation on port
P3.0 and P3.1 with J13 and J14 closed at position 2+3.
The RS-232 interface enables connection of the module to a COM
port on a host-PC. In this instance the RxD0 line of the transceiver is
connected to the TxD line of the COM port; while the TxD0 line is
connected to the RxD line of the COM port. The Ground potential of
the phyCORE-167CR/167CS circuitry needs to be connected to the
applicable Ground pin on the COM port as well.
The microcontroller’s on-chip UART does not support handshake
signal communication. However, depending on user needs, handshake
communication can be software emulated using port pins on the
microcontroller. Use of an RS-232 signal level in support of hand-
shake communication requires use of an external RS-232 transceiver
not located on the module.
If the module is populated with a UART device at U7, a supplemental
RS-232 transceiver can be mounted at position U5. This latter device
enables RS-232 signal conversion of the handshake signals supported
by the external UART.
Note:
Jumpers J21 and J22 must remain closed on the
phyCORE-167CR/167CS. If they are open, no serial communication
is possible, hence PHYTEC FlashTools or the BOOT monitor will not
function properly.