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

6.4.4. SERIRQ Interrupt Event

The LPC bridge supports 16 lines IRQ/Data serializer by sampling the event of SERIRQ signal from the LPC interface. A SERIRQ cycle transfer consists of three frame types:
  • Start Frame: The agent device drives the SERIRQ line low to indicate the start of IRQ transmission.
  • IRQ/Data Frames (several): Peripherals transmit the IRQ information. The eSPI bridge host supports 16 IRQ data frames. During the sample phase, the SERIRQ device must drive the SERIRQ low, if and only if, its detected IRQ/Data value is low. And if its detected IRQ/Data value is high, SERIRQ must be left tri-stated. During the recovery phase, the device must drive the SERIRQ high, if and only if, it had driven the SERIRQ low during the sample phase.
  • Stop Frame: The Host Controller initiates a Stop frame to terminate SERIRQ activity after all IRQ/Data Frames have completed. A Stop Frame is indicated when the SERIRQ is low for two clock cycles. Stop frame occurs at 53-54 clock cycles past the Start frame.
Figure 25. SERIRQ Event Timing Diagram
The start frame is 4 clock cycles, stop frame is 2 clock cycles, and the IRQ/Data frames clock cycles are stated below:
Table 34.  IRQ/Data Frame Clock Period
IRQ/Data Frame Sampled Signal Number of Clocks after Start Frame
1 IRQ0 2
2 IRQ1 5
3 SMI# 8
4 IRQ3 11
5 IRQ4 14
6 IRQ5 17
7 IRQ6 20
8 IRQ7 23
9 IRQ8 26
10 IRQ9 29
11 IRQ10 32
12 IRQ11 35
13 IRQ12 38
14 IRQ13 41
15 IRQ14 44
16 IRQ15 47
17 Reserved -
Once the LPC bridge samples and derives the SERIRQ event, it translates the IRQ/Data Frame into VW index bit as below:
Table 35.  SERIRQ IRQ/Data Frame to VW Index Group Mapping
SERIRQ Sampled Signal VW Index Group VW Data Bit
SMI# 6h Bit 2
IRQ0 to IRQ15 00h Bit 0 - Bit 15
IRQ VW information can be sent to the eSPI host only through GET_VWIRE command during transition period.
Table 36.  VW Information via Transition Period
Interrupt Source Type Interrupt Source Level Agent to Host IRQ Virtual Wire (Active High)
Active low 0 → 1 De-assertion. IRQ VW (Level=’0’) sent.
Active low 1 → 0 Assertion. IRQ VW (Level=’1’) sent.