8
FASTCOM SERIAL SETTINGS
These settings can be accessed using the application serialgt.exe (Windows 98/NT) or in the Fastcom Serial Settings tab of
the Fastcom AsyncPCI Communications Port Properties dialog (Windows 2K/XP), which is found in the device manager under
Ports (COM & LPT).
CLOCK/4
Clock divisors of 1 and 4 are available. Clearing the checkbox selects a divisor of 1 and setting the checkbox
selects a divisor of 4. It is best to leave this box unchecked.
RX Trigger
Determines the number of bytes that will be stored in the receive FIFO on the 16C854 before an interrupt is
triggered. Valid values are from 1 to 128 bytes. The optimal setting is 64 bytes. For 16C550 compatibility,
set to 8.
TX Trigger
Determines the number of bytes remaining in the transmit FIFO on the 16C854 before an interrupt is
triggered. Valid values are from 0 to 127 bytes. The optimal setting is 64 bytes. For 16C550 compatibility,
set to 0.
TX Write Size
Determines the number of bytes sent to the board at a time. Valid values are from 1 to 128. This number
plus the TX Trigger value should not exceed 128. The optimal value is 64. For 16C550 compatibility, set to
16 or 1.
BaudTable (Win2K/XP)
This table represents the standard baud rates that the Fastcom card will currently support. If you wish to use
a non-standard baud, you may enter it into one of the boxes on the table and hit the tab key
(do not hit enter,
hitting enter will exit the program). This will set the on-board clock generator to a frequency (see Input
Frequency below) that will divide down to the new baud rate. The rest of the table will also be updated to
reflect other bauds that can be used with the calculated clock frequency. If you wish to return to the standard
rates, you can set the top box to 115200 and hit tab; the rest of the bauds will be filled in.
Note: The baud rates that you set will not be available to standard Windows applications like HyperTerminal.
The new rates will be available to you in your code or in applications that allow user defined baud rates such
as TTY2, which can be found on the Fastcom disk (Fastcom_CD\Fastcom_disks\AsyncPCI\tty\tty2.exe).
THIS SETTING=THIS BITRATE (Baud Rate Substitution Table) (Win98/NT)
Under THIS SETTING you will see the standard PC baud rates, from 115.2K to 300. If you wish to use a
baud rate not shown, type the baud rate in the box next to 115200 (e.g., type 128K as 128000), and hit the
tab key.
Do not hit enter.
Hitting enter will exit the program. If the baud rate changes after you tab, move to
the next box down and try again. Continue moving down until the baud rate stays the way you want it. Now
note the standard PC baud rate to the left of the box you ended on. You will select this standard baud rate to
set up your com ports, and the baud rate you require will be substituted. If you receive an error message
stating that the maximum baud rate was exceeded, change the Clock Divisor to 1 and try again.
INPUT FREQUENCY
This is the calculated frequency required to generate the baud rate requested. When you click OK on the
Fastcom Serial Settings page, this frequency is sent to the clock generator and the new baud rates will be
available.
OTHERS
Auto 485, CTS Disable, 485 Enable, RX Echo Disable, Enable Source, and Sample Rate do not apply to this
board. Do not change these options as they will have no positive affect on settings for this board and may
cause instability.
