Port 1 Clock Select / Interrupt Status; Port 2 Clock Select / Interrupt Status - Measurement Computing PCI-COM422/485 Series User Manual

31:8 7
x x
The UART ports are 16C550 compatible. See any 16C550 data sheet for register functions.

4.2.2 PORT 1 CLOCK SELECT / INTERRUPT STATUS

7 6
PORT1 PORT1
TXSEL1 TXSEL0
7 6
PORT1 PORT1
TXSEL1 TXSEL0
INTx Interrupt status for each port. The same signals are connected to this read register for all ports.
CKSEL1:0 UART clock select. This allows for data rates to 460.8 Kbps and different data rates on
TXSEL1:0 Transmit data control select. This allows for controlling the Transmit Data driver. The
default mode for RS485 is 'Auto Enable'. This mode is recommended for all RS485 communication.
ECHOEN 1:0 Echo enable/disable. When set low, this enables the hardware to echo the transmitted data to the
receiver. When set high, this disables the 'Receiver Enable' control signal on the RS485 transceiver while data is
being transmitted. Therefore, the transmitted data are not echoed to the receiver.
For TXSEL0:1 = '11', ECHOEN has no function since this is full duplex mode and the transmitter and receiver are
always 'ON'.

4.2.3 PORT 2 CLOCK SELECT / INTERRUPT STATUS

READ/WRITE
6 5
x x
AVAILABLE PORTS:
PCI-COM422/485:
PCI-COM422/485-2:
BADR2 + 07 hex
5 4
PORT1 PORT1
CKSEL1 CKSEL0
5 4
PORT1 PORT1
CKSEL1 CKSEL0
each port. These settings are per port:
CKSEL1 CKSEL0
0
0
1
TXSEL1 TXSEL0
0
0
1
1 1
BADR3 + 07 hex
4 3
X x
PORT 1
PORTS 1-2
READ
3 2
- -
WRITE
3 2
PORT1 -
ECHOEN
UART CLOCK
0 1.8432 MHz
1 3.6864 MHz
0 7.3728 MHz
Transmit Control
0 Auto Enable
1 RTS Enable
0 DTR Enable
Transmit 'ON'
13
2 1
INT INTPOL INTE
1 0
INT2 INT1
1 0
- -
Max Data Rate
115.2 kbps
230.4 kbps
460.8 kbps
Duplex Mode
Half
Half
Half
Full – RS422 Mode
0