Embedian, Inc.
49
SMART-BEE User’s Manual Document Revision v.1.2
3.2.3.1. Asynchronous Serial Ports Header: CN12 and CN13
The SMARC T335X Evaluation Carrier supports three serial ports defined
in the SMARC specification. They are SER0, SER1 and SER3. SER3 is
also used as a serial debug port that is described in section 3.1.3.1. The
Evaluation Carrier has EIA RS232/RS422/RS485 compliant signal levels
and polarities. Per the SMARC specification, one of the three ports (SER0)
have RTS/CTS handshaking, and two (SER1 and SER3) have TX and RX
data only, without handshaking.
The Evaluation Carrier runs SER0 and SER1 through one transceiver and
SER3 through a 2nd transceiver. The Evaluation Carrier could also runs
SER0 via JP2 setting through a SN75HVD11D transceiver to become a
RS422 or RS485 signals.
A 10-way box header to DB9 cable with 20cm long comes with the
evaluation kit for users easily testing the functions and is shown as
follows.
Figure 11: 10-way box header to DB9 cable
The red line on the cable should align to pin 1 of the header.
The following table shows the pin-out of the CN12 and CN13
asynchronous serial port header.
