SBC35-C398/Configuration
v1.0
www.winsystems.com
Page 32
8.5.18 COM 2, 3, 4, & 5 (J18)
The SBC35-C398Q (not available on the SBC35-C398S and SBC35-C398DL) provides a
COM Interface at J18. COM 2 uses the EXAR SP339E multi-protocol transceiver and
supports RS-232, RS-422, and RS-485 modes. RS-232 can transmit and receive data
up to 1 Mbps, while RS-422/485 modes are capable of data transmission speeds up to
5 Mbps. The SP339E transceiver includes programmable line termination for the RS-
422/485, loopback mode, and slew rate.
COMS 3, 4, & 5 use Linear Tech LTC2854 RS-422/485 transceivers with programmable
120 ohm termination. All three COM ports are capable of transmitting and receiving data
up to 5 Mbps.
COM5 is multiplexed with the IO60 UART signals. If a module with UART support is
plugged into the IO60 connector, the COM5 UART signals will be routed to the IO60
expansion bus, not J18.
Linear Tech Transceiver (COMS 3, 4, & 5) table
WinSystems provides scripts that configure selected modes for each UART with the
example operating systems. The settings used by the scripts to configure different
communication protocols are shown in the Linear Tech Transceiver (COMS 3, 4, & 5)
table. A termination resister may be necessary for accurate RS-485/422
communication, but must be removed when the lines are used for RS-232.
Rx485EN
RX422EN
HD3_TE
FD3_TE
RS485 W/Term
0
1
1
0
RS485 W/O Term
0
1
0
0
RS422 W/RCVR Term
1
0
0
1
RS422 W/O RCVR Term
1
0
0
0
