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

6.4.1. FIFO Implementation

All FIFOs are used in peripheral channel to buffer up the incoming transactions. When the eSPI-to-LPC bridge is busy transferring data down the LPC interface, the transactions from the eSPI host are stored using the PC_RXFIFO or NP_RXFIFO until the bridge is idle. The PC_RXFIFO stores posted transactions while the NP_RXFIFO stores non-posted transactions.

The RXFIFOs can store more than one eSPI transaction (command byte, header byte and write data byte) until it is full. When the FIFO depth is less than MAX_PC_PAYLOAD_SIZE + 1 complete header + 1 command byte or 1 complete header + 1 command byte for NP_RXFIFO , the PC_FREE/NP_FREE status register bit is de-asserted.

The Pre_RXFIFO stores an incoming eSPI transaction for CRC error checking purposes. CRC error check is performed after pushing the last byte of a eSPI transaction into Pre_RXFIFO. If CRC error is high, then the eSPI transaction is dropped to avoid translation into a LPC transaction. If CRC error is low, the eSPI transaction is pushed into NP_RXFIFO or PC_RXFIFO for translating into a LPC transaction.

The PC_TXFIFO stores response transaction from the downstream LPC devices. The PC_ AVAIL status register bit goes high only when a complete response transaction is stored in the PC_TXFIFO.

The Pre_TXFIFO stores an incoming LPC transaction for error checking purposes. In the event of LPC transaction abort or LPC transaction sync error, the transaction is dropped from the Pre_TXFIFO. The transaction is pushed into PC_TXFIFO provided that there is no error, then to eSPI host.

All the FIFOs are 8-bit wide. The figure below shows the content of the RXFIFO which can store one complete eSPI transaction.
Figure 24. RXFIFO Contents