Chapter5 ATSerial Hardware Installation, Verification, and Configuration
©NationalInstruments Corporation 5-9 SerialHardware and Software for Windows
Use FIFO Buffers
FIFOb uffers are present on the 16550-compatible UARTs—one for the
transmitterand one for the receiver. The Receive Buffer control sets the
numbero fc haractersreceived in the FIFO before the PC is interrupted to
read the data. The Transmit Buffer control sets the maximum number of
byteswritten to the FIFO in a block when the PC is interrupted to write the
data. When you configure FIFO settings, consider the following points:
•Youcan select larger FIFO buffer sizes to reduce the number of
interruptsyour PC r eceivesand therefore minimize system overhead.
•Ift ransfer rates are high, you can lower the Receive Buffer value to
preventoverrun errors due to interrupt latency.
•Ifyour data transfer sizes are small and your Receive Buffer value is
aboveyour data sizes, your system is less efficient. Therefore, set the
ReceiveBuffer value below your data sizes.
Restore Defaults
Toreset the fields totheir default values at any t ime,click on theRestore
Defaults button.
Windows Me/9x
Install the Software
Installthe NI-Serial software for Windows Me/9xbefore you install the
hardware.
1. Select Start»Settings»Control Panel.
2. Double-clickon the Add/Remove Programs icon in the Control Panel
to launch the Add/RemovePrograms applet . The Add/Remove
Programs dialog box appears.
3. ClickontheInstallbutton.
4. When prompted, insert the NI-Serial Software for Windows
2000/NT/Me/9x CD,and click on the Next button toproceed.
The software installation wizard begins.
Thesetup wizard guides you through the necessary steps to install the
NI-Serials oftware.You can go back and change values where
appropriate byclicki ng on the Back button.You can exit the setup
whereap propriate byclickin g on the Cancel button.