SMARC T335x Carrier Board Hardware Design Guide, Document Revision 1.2
2.8 Serial COM Port Interface
The
SMARC
specification defines up to four asynchronous serial ports
interface in CMOS logic level. The ports are designated
SER0
~
SER3
. Ports
SER0
and
SER2
are 4 wire ports (2 data lines and 2 handshake lines). Ports
SER1
and
SER3
are 2 wire ports (data only).
SMARC T335X
module offers three serial ports interface (
SER0
,
SER1
and
SER3
) that enable interfacing COM ports on the carrier board design.
SER1
is
used for software debug port by default. The serial ports interface bus can
support standard RS-232, RS422 and RS485 serial communication.
The signals for Serial COM ports on the
T335X
module connectors are 3.3V
logic-level signals. External transceiver devices are necessary for the
conversion of the logic-level signals to the desired physical interface such as
RS232, RS422 or RS485 serial communication.
Following section shows the pinouts of asynchronous serial port interface of
T335X
.