Embedded Peripherals IP User Guide

ID 683130
Date 10/24/2025
Public
Document Table of Contents
1. Introduction 2. Avalon® -ST Serial Peripheral Interface Core 3. SPI Core 4. SPI Agent/JTAG to Avalon® Host Bridge Cores 5. Intel eSPI Agent Core 6. eSPI to LPC Bridge Core 7. Ethernet MDIO Core 8. Intel FPGA 16550 Compatible UART Core 9. UART Core 10. Lightweight UART Core 11. JTAG UART Core 12. Intel FPGA Avalon® Mailbox Core 13. Intel FPGA Avalon® Mutex Core 14. Intel FPGA Avalon® I2C (Host) Core 15. Intel FPGA I2C Agent to Avalon® -MM Host Bridge Core 16. EPCS/EPCQA Serial Flash Controller Core 17. Intel FPGA Serial Flash Controller Core 18. Intel FPGA Serial Flash Controller II Core 19. Intel FPGA Generic QUAD SPI Controller Core 20. Intel FPGA Generic QUAD SPI Controller II Core 21. Interval Timer Core 22. Intel FPGA Avalon FIFO Memory Core 23. On-Chip Memory (RAM and ROM) Intel FPGA IP 24. On-Chip Memory II (RAM or ROM) Intel FPGA IP 25. PIO Core 26. PLL Cores 27. DMA Controller Core 28. Modular Scatter-Gather DMA Core 29. Scatter-Gather DMA Controller Core 30. Video Sync Generator and Pixel Converter Cores 31. Intel FPGA Interrupt Latency Counter Core 32. Performance Counter Unit Core 33. Vectored Interrupt Controller Core 34. System ID Peripheral Core 35. Intel FPGA GMII to RGMII Converter Core 36. HPS GMII to RGMII Adapter IP 37. Intel FPGA MII to RMII Converter Core 38. HPS GMII to TSE 1000BASE-X/SGMII PCS Bridge Core IP 39. Intel FPGA HPS EMAC to Multi-rate PHY GMII Adapter Core 40. Intel FPGA MSI to GIC Generator Core 41. Cache Coherency Translator IP 42. Altera ACE5-Lite Cache Coherency Translator

8.4.3. iir

Identifier Title Offset Access Reset Value Description
iir Interrupt Identity Register 0x8 R 0x00000001 Returns interrupt identification and FIFO enable/disable when read.
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
-
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
fifose id
Table 69.  iir Fields
Bit Name/Identifier Description Access Reset
[31:8] Reserved R 0x0
[7:6] FIFOs Enabled (fifose) The FIFOs Enabled is used to indicate whether the FIFO's are enabled or disabled. R 0x0
[5:4] Reserved R 0x0
[3:0] Interrupt ID (id) The Interrupt ID indicates the highest priority pending interrupt. Refer to the Table 70 table below for more details. R 0x1
Table 70.  Interrupt Priority
IIR ID Interrupt Priority
4'b0000 Modem status 5th
4'b0001 No interrupt pending 6th
4'b0010 THR empty (reflect TX_Low empty threshold if ARF[0] is '1) 4th
4'b0100 Received data available 2nd
4'b0110 Receiver line status 1st
4'b1100 Character timeout 3rd