Quatech RS-422 - Manual (Page 16)

4.4 Quatech Modem Control Register
The Quatech Modem Control Register can be used to setup each port. To
access QMCR write a 0xBF to the LCR(base + 3) and a 0x10 to the Opt
Reg(base+7). This will allow the user read/write access to QMCR. The QMCR of the
entire DSCLP-200/300, as shown in Figure 9a. The individual bits are cleared as the
interrupting ports are serviced. The QMCR will need to be written to after the setup by
writing a 0x00 to (base+B).
00 - TXEN “Auto”
01 - TXEN=DTR
10 - TXEN=RTS
11 - TXEN TOGGLES DURING X-MIT
1-0
0 - AUXOUT=RTS
1- AUXOUT=TCLK
2
0 - RCLK=TCLK,CTS=AUXIN
1 - RCLK=AUXIN, CTS=RTS
3
0 - Bits 2 and 3 are used
1 - RCLK=TCLK,CTS=RTS,
AUXOUT=AUXIN
4
0 - RXEN=1
1 - RXEN=!TXEN
5
0 (always 0) 6
0 (always 0) 7 (MSB)
Description Bit
Figure 9a --- Quatech Modem Control Register
DSCLP-200/300 User's Manual 11