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

5.1.1. Link Layer

In the Link Layer, the Condition Detector block shifts the serial data bus in (receive) and out (transmit) in eSPI clock domain. The input serial data is translated into parallel form and sent to transaction layer. The parallel data bus from the transaction layer is translated into serial form in the condition detector and sent out as the eSPI output data.

During the single I/O mode, the espi_data[1:0] I/O pins are unidirectional to form a unidirectional data bus. Data is driven using espi_data[0] during the command phase, and espi_data[1] the during response phase. The eSPI agent is required to tri-state espi_data[1] during command phase as espi_data[1] can be driven by eSPI host such as when initiating an In-Band Reset command.

During the dual I/O mode, the espi_data[1:0] I/O pins are bidirectional to form a bidirectional data bus. All the command and response phases are transferred over the two bidirectional pins at the same time, which effectively doubles the transfer rate than that of the single I/O mode.

During the quad I/O mode, the espi_data[3:0] I/O pins are bi-directional data bus. All the command and response phases are transferred over the four bi-directional pins at the same time, which effectively doubles the transfer rate than that of the dual I/O mode.

During eSPI transaction, each field is shifted in a defined order. For multibyte fields, the shifting order is as following:
  • Header (length and address): Most Significant Byte (MSB) to Least Significant Byte (LSB)
  • Data: LSB to MSB
  • Status: LSB to MSB
Figure 18. Byte Ordering on the eSPI BusThis is an example of a host initiating a peripheral channel memory read.