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

37.4.2. Transmit Interface

The transmit logic takes 4-bit (nibble) data through the MII transmit interface from the MAC and transmits the same through the RMII interface to a RMII PHY. The following figure shows the timing relations between the different signals in a MII TX frame.
Figure 160. MII TX Frame

The parameter MBPS determines data rate of the transmit interface. If MBPS is set to 1, the TX speed in 100 Mbps; else if the MBPS is set to 0, the TX speed is 10 Mbps. The frequency of the TX clock is 25 Mhz in 100 Mbps mode and 2.5Mhz in 10Mbps mode. The IP core provides TX clock to MII MAC.

During transmission, the MII MAC asserts the m_tx_en signal and transmit 4-bit of data at each cycle of the TX clock. When there is an error in the transmission, the MII MAC asserts the m_tx_err signal synchronous to TX clock. The following figure shows a TX frame with m_tx_err.
Figure 161. TX Frame with Error Signal
On detecting an TX error, the core transmits 01 pattern for the rest of the transmission over the output RMII interface, so that the frame fails the cyclic redundancy check (CRC).