When the IP has received an INTx interrupt, the Root Port Interrupt Decode 2 register is set. If the Root Port Interrupt Decode 2 Mask register is also set, the interrupt_out pin is asserted. After receiving this interrupt, the user application must follow this procedure to service the interrupt:
- Optional: Write 0 to the Interrupt Decode 2 Mask register to deassert an interrupt line while the interrupt is being serviced.
- Read the Root Port Interrupt Decode 2 register to check which interrupt line is currently asserted.
- Repeat step 2 until all interrupt lines are deasserted. The interrupt line is automatically cleared when the IP receives the INTx Deassert Message corresponding to that interrupt line.
- If step 1 was executed, write 1 to the Interrupt Decode 2 Mask register to re-enable an interrupt line for future INTx interrupt.