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4. Jumper Setting
SEH-9450-LAS
27
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
RTS#
R
D
1ΚΩ
JCOM1: 14-6
JCOM1: 15-6
SOUTB
6.2ΚΩ
6.2ΚΩ
4.7
KΩ
4.7
KΩ4.7KΩ4.7KΩ4.7KΩ
4.7
KΩ
10 5
61
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 Read/Write Register
W Transmitter holding Register THR
0
R Receiver buffer Register RBR
02F8H
1 W Divisor latch Register (LSB) DLL
1 W Divisor latch Register (MSB) DLM
02F9H
0 W Interrupt enable Register IER
02FAH X R Interrupt ID Register IIR
02FBH X W Line control Register LCR
02FCH X W Modem Control Register MCR
02FDH X R Line status Register LSR
02FEH X R Modem Status Register MSR
02FFH X R/W Scratch Register SCR