Filter
Top Products
Chapter 5 AT Serial Hardware Installation, Verification, and Configuration
Serial Hardware and Software for Windows 5-18 ni.com
Use FIFO Buffers
The FIFO buffer control is available by clicking on the Advanced button
on the Port Settings tab. FIFObuffers are present on the 16550-compatible
UARTs—one for the transmitter and one for the receiver. The receiver
FIFO trigger denotes the number of characters received in the FIFO before
the PC is interrupted to read the data. The transmit FIFO trigger denotes the
maximum number of bytes written to the FIFO in a block when the PC is
interrupted to write the data. Consider the following points when selecting
FIFO settings:
• You can select larger FIFO settings to reduce the number of interrupts
and therefore minimize system overhead.
• If transfer rates are high, you can lower receive FIFO settings to
prevent overrun errors due to interrupt latency.
• If data transfer sizes are small, selecting receive FIFO settings just
above data sizes can reduce efficiency, so select lower settings.
Note
If you want your serial hardware ports to use the names COM1, COM2, COM3,or
COM4, refer to the Common Questions section of Appendix D, Troubleshooting and
Common Questions.
Windows NT
Installing the Microsoft PnP ISA Enabler Driver
When you install an AT board, you must install the PnP ISA Enabler
Driver.
The AT serial hardware is Plug and Play. Windows NT 4.0 does not support
Plug and Play. In order for Windows NT to detect and install the Plug and
Play hardware, you must install the PnP ISA Enabler driver included on
your Windows NT 4.0 CD-ROM. Complete the following steps to install
the driver:
1. Locate the
Pnpisa.inf
file in the
Drvlib\Pnpisa\X86
folder on
the Windows NT 4.0 CD-ROM.
2. Right-click on the
Pnpisa.inf
file, then select Install on the menu
that appears.
3. Restart the computer.