Setting Driver Options
16
Chapter 4
Document Number 3PCI-0712m
Note:
For proper operation the DIP switches on the PCI card must be
set for the same mode. Refer to Chapter 2 for more information on
configuring the DIP switches.
2.
The
Direction control delay (bit times)
box allows you to set the
length of time the Transmit driver continues to be enabled after the
last bit of data in the transmit register has been sent. The purpose of
this setting is to maintain the transmission line in a know (idle) state
until the data has reached its destination. If the line is released too
soon it can pick up noise that could cause problems on the
communications system. This parameter is preset to a value of 10
bit times and typically will not have to be changed. For longer
transmission lines this value may have to be increased.
Setting the Hardware Handshaking Level
The
Hardware handshaking Hysteresis level (characters)
parameter allows you to
set how long the local UART will continue to accept data after its receive buffer has
reached the point at which it asks the computer to transfer the data to program memory.
When this point is reached the UART de-asserts the RTS hardware handshake line
(which is connected to the remote UART‘s CTS line), stopping the remote device from
sending data until its CTS line is re-asserted. This will occur when the local receive
FIFO buffer has been cleared. The default value for this parameter is 0. Typically this
value will not need to be changed.
Changing the COM Port Name/Number
1.
To change the COM port number assigned to the port, click the
COM Port
Name
arrow and select the new
COM Port Name
from the list.
Available names for COM numbers are shown. Select a new number from
those not ―in use‖. COM numbers from COM1 to COM256 may be available.
COM numbers ―in use‖ may be used by motherboard ports, modems, virtual
COM ports for network serial server devices or FAX modems. Formerly
installed USB to serial adaptors, PCI cards or other hardware may have
reserved a COM number. The device may need to be added back to the
system, then the software removed. Advanced editing of the registry may
required to clean up the problem. Special permissions are required with 2000
or XP.
