Interrupt Controller

Class Notes

Commercial Documentation

Here is the full documentation of the AXI Interrupt Controller hardware. Like the other hardware manuals, you should pay closest attention to the Register Space section.

Base Address

The AXI Interrupt Controller is located at the base address provided by XPAR_AXI_INTC_0_BASEADDR (make sure to #include <xparamters.h> like in the previous lab).


Based on the above, there are four different things that need to be enabled during setup before interrupts will begin working.

Needs Enabling Code Location
Interval Timer irq output intervalTimer_enableInterrupt(). Called by your application code on each timer you want to use for interrupts.
Interrupt Controller input line interrupts_irq_enable(). Called by your application code for each timer you want to use for interrupts.
Interrupt Controller irq output Set both enable bits on the Master Enable register during interrupts_init().
ARM Processor Input Need to call the three functions (armInterrupts_init(), armInterrupts_setupIntc(interrupts_isr), and armInterrupts_enable()) to initialize and enable the interrupt input, as well as register your ISR. This should be done within interrupts_init().

Also, every time a timer interrupt occurs, there are two places where the interrupt needs to be acknowledged, otherwise it will continue indefinitely!

Needs Acknowledging Code Location
Interval Timer Call intervalTimer_ackInterrupt() from application code.
Interrupt Controller Acknowledge interrupt from within your ISR in your interrupt controller driver.