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

2.1.2. Operation

The Avalon® -ST SPI core waits for the nSS signal to be asserted low, signifying that the SPI host is initiating a transaction. The core then starts shifting in bits from the input signal mosi. The core packs the bits received on the SPI to bytes and checks for the following special characters:
  • 0x4a—Idle character. The core drops the idle character.
  • 0x4d—Escape character. The core drops the escape character, and XORs the following byte with 0x20.

    For each valid byte of data received, the core asserts the valid signal on its Avalon® -ST source interface and presents the byte on the interface for one clock cycle.

    At the same time, the core shifts data out from the Avalon® -ST sink to the output signal miso beginning with from the most significant bit. If there is no data to shift out, the core shifts out idle characters (0x4a). If the data is a special character, the core inserts an escape character (0x4d) and XORs the data with 0x20.

    The data shifts into and out of the core in the direction of MSB first.

Figure 2. SPI Transfer Protocol
Table 3.  SPI Transfer Protocol Specification
Symbol Description Minimum Maximum Unit
TL The worst recovery time of sclk with respect with nSS. ½ SPI clock - Clock cycle
TT The worst hold time for MOSI and MISO data. ½ SPI clock -
TI The minimum width of a reset pulse required by Intel FPGA families. 1 SPI clock -