National Instruments PCI-8430, Manual

Page: 93 / 237

Performance on LabVIEW Real-Time
NI-Serial users on LabVIEW Real-Time have control over whether
secondary interrupt handling is enabled. When secondary interrupt
handling is enabled, I/O is processed at a priority lower than time-critical.
Using secondary interrupt handling reduces jitter for time-critical loops
and makes serial hardware interrupts more deterministic. However, it
may also reduce I/O performance and can increase the possibility of
overflowing the RX FIFO buffer. Secondary interrupt handling is a setting
at the system-wide level and is enabled by default.
To enable or disable this feature, complete the following steps:
1. Copy to your host the
niserial.dbs
file in the
/ni-rt/system
directory
on the RT target.
2. In the
niserial.dbs
file, find the entry SecondaryInterrupts and
modify it accordingly:
To enable secondary interrupt handling, set
SecondaryInterrupts to 1.
To disable secondary interrupt handling, set
SecondaryInterrupts to 0.
3. Download the updated
niserial.dbs
file to the target, overwriting the
existing file in the
/ni-rt/system
directory.
4. Reboot your RT target.