Contec BX220 Series - Page 82

6. Appendix
BX-220 User’s manual
73
Table 6.3. Function of Each Register < 1 / 4 >
THR: Transmitter Holding Register [DLAB=0]
D7 D6 D5 D4 D3 D2 D1 D0
bit7
MSB
bit0
LSB
Register dedicated to write transmitted data to
03F8H
I/O address Description
RBR: Reciever Buffer Register [DLAB=O]
D7 D6 D5 D4 D3 D2 D1 D0
bit7
MSB
bit0
LSB
Register dedicated to read received data from
03F8H
DLL: Divisor Latch (LSB) [DLAB=1]
D7 D6 D5 D4 D3 D2 D1 D0
bit7
MSB
bit0
LSB
Baud rate setting register (LSB)
03F8H
D7 D6 D5 D4 D3 D2 D1 D0
bit7
MSB
bit0
LSB
Baud rate setting register (MSB)
03F9H
IER: Interrupt Enable Register [DLAB=0]
D7 D6 D5 D4 D3 D2 D1 D0
0
03F9H
DLH: Divisor Latch (MSB) [DLAB=1]
0 0 0 EMS ELSI
ETHREI
ERDAI
Received data
Interrupt enable
Received data register empty
Interrupt enable
Receiver line status
Interrupt enable
Modem status interrupt enable
[Always used at 0.]
1: Enable interrupt
0: Disable interrupt