RIO Developer Essentials Guide for Academia
RT guide
RT programming: Interrupts
Use an onboard timer or an external event interrupt request (IRQ) to immediately execute a task.
Summary
The Academic RIO Device default FPGA personality includes three types of interrupt sources: digital input transition, analog input threshold crossing, and timer. Each interrupt request (IRQ) suspends the current process to run a designated callback VI; the callback VI should be designed to run as quickly as possible so as not to unnecessarily delay other processes.
Up to eight independent timers are available. External inputs sources are available on the MXP-A/Bank A connector only (digital inputs 0, 1, 2, and 3; analog inputs 0 and 1).
Code examples
- Run a callback VI each time the FPGA-based interval timer generates an IRQ; the timer interval can be as low as 1 microsecond and as long as about 71.6 minutes (2^32 microseconds).
- Run a callback VI each time an external event such as a digital input transition or analog threshold crossing occurs.
For more information
- Using Callback VIs to Handle Interrupts (myRIO Toolkit) (http://zone.ni.com/reference/en-XX/help/373925C-01/myriohelp/myrio_use_callback_vi)
Guidelines for the design of VIs that will serve as callback VIs