Contec Single Board Computer Half-size PICMG 1.3 with LAN, Audio, SATA SEH-9450-LAS User Manual page 34

Setting the RS-422/RS-485 receiver disable control jumper
When the RS-422/RS-485 port is used, the RTS signal is used for driver enable control Connecting
JCOM1 Pins 14 and 16 disables the receiver at the same time, preventing the port from receiving output
data to an external device.
RS-422/485 setting
4.7 K Ω
4.7 K Ω 4.7 K Ω
JCOM1: 14-6
1ΚΩ
JCOM1: 15-6
Figure 4.1. RS-422/485 Setting
I/O addresses and instructions
The table below lists I/O addresses for use as SERIAL2.
Table 4.5. I/O Addresses and instructions
I/O address DLAB
0
02F8H
1
1
02F9H
0
02FAH X
02FBH X
02FCH X
02FDH X
02FEH X
02FFH X
SEH-9450-LAS
RTS#
4.7 K Ω 4.7 K Ω
R
4.7 K Ω
SOUTB
D
Read/Write
W Transmitter holding Register
R Receiver buffer Register
W Divisor latch Register (LSB)
W Divisor latch Register (MSB)
W Interrupt enable Register
R Interrupt ID Register
W Line control Register
W Modem Control Register
R Line status Register
R Modem Status Register
R/W Scratch Register
6.2ΚΩ
10 5
6.2ΚΩ
6 1
Register
THR
RBR
DLL
DLM
IER
IIR
LCR
MCR
LSR
MSR
SCR
4. Jumper Setting
27