External Interrupts

External Interrupts

The Challenge/Onyx hardware includes support for generating and receiving external interrupt signals. Four jacks for outgoing signals are available on the master IO4 board. Your program can change the level of these lines individually. Two jacks for incoming interrupt signals are also provided. The input lines are logically OR'd together and presented as a single interrupt; your program cannot distinguish one input line from another.

The electrical interface to the external interrupt lines is documented at the end of the ei(7) reference page.

Your program controls and receives external interrupts by interacting with the external interrupt device driver. This driver is associated with the special device file /dev/ei, and is documented in the ei(7) reference page. (External interrupt support and the ei(7) page are first available in IRIX 5.3.)

For programming details of the external interrupt lines, see the IRIX Device Driver Programmer's Guide. You can also trap external interrupts with a user-level interrupt handler (see "User-Level Interrupt Handling"); this is also covered in the IRIX Device Driver Programmer's Guide.