Contec SPI-8451-LVA - Manual (Page 44)

4. Jumper Setting
SPI-8451-LLVA, SPI-8452-LLVA, SPI-8451-LVA
37
RS-485 Setting
RTS#
JP8: 7-8
TXD#
JP7: 7-8
JP7: 5-6
D
R
RXD#
SERIAL2
1
2
3
4
5
6
7
8
9
JP8: 5-6
JP8: 4-6
120 Ω
120 Ω
DATA-
DATA+
Figure 4.2. RS-485 Setting
I/O addresses and instructions
The table below lists I/O addresses for use as SERIAL2.
Table 4.2. 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