This model shows how to support asynchronous read/write using an external TTL signal firing an interrupt on the parallel port. This event invokes a function-call subsystem serving as an interrupt service routine (ISR). Data is exchanged between the asynchronous task and the rest of the model (rate monotonic task) using Asynchronous Double Buffer blocks.
For more information on using the parallel port as an interrupt source, see the xPC Target documentation on using parallel ports.
To run this model, the following setup is required:
Connect an external TTL signal source such as a Pulse Generator to the ACK input, pin 10 on the parallel port. During real-time application execution, the function-call subsystem will then be executed whenever a TTL low-high signal transition occurs.
If not yet done, boot the target computer as an xPC Target™ machine and build the real-time application.
See also xpcasynctrans