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

29.7.7. alt_avalon_sgdma_construct_mem_to_stream_desc()

Prototype: void alt_avalon_sgdma_construct_mem_to_stream_desc(alt_sgdma_descriptor *desc, alt_sgdma_descriptor *next, alt_u32 *read_addr, alt_u16 length, int read_fixed, int generate_sop, int generate_eop, alt_u8 atlantic_channel)
Thread-safe: Yes.
Available from ISR: Yes.
Include: <altera_avalon_sgdma.h>, <altera_avalon_sgdma_descriptor.h>, <altera_avalon_sgdma_regs.h>
Parameters: *desc—a pointer to the descriptor being constructed.

*next—a pointer to the “next” descriptor. This does not need to be a complete or functional descriptor, but must be properly allocated.

*read_addr—the first read address for the SG-DMA transfer.

length—the number of bytes for the transfer.

read_fixed—if non-zero, the SG-DMA reads from a fixed address.

generate_sop—if non-zero, the SG-DMA generates a SOP on the Avalon® -ST interface when commencing the transfer.

generate_eop—if non-zero, the SG-DMA generates an EOP on the Avalon® -ST interface when completing the transfer.

atlantic_channel—an 8-bit Avalon® -ST channel number. Channels are currently not supported. Set this parameter to 0.

Returns: void
Description: This function constructs a single SG-DMA descriptor in the memory specified in alt_avalon_sgdma-descriptor *desc for an Avalon® -MM to Avalon® -ST transfer. The destination (write) data for the transfer goes to the Avalon® -ST interface connected to the SG-DMA controller's streaming write port. The function sets the OWNED_BY_HW bit in the descriptor's control field, marking the completed descriptor as ready to run. The descriptor is processed when the SG-DMA controller receives the descriptor and the RUN bit is 1.

The next field of the descriptor being constructed is set to the address in *next. The OWNED_BY_HW bit of the descriptor at *next is explicitly cleared. Once the SG-DMA completes processing of the *desc, it does not process the descriptor at *next until its OWNED_BY_HW bit is set. To create a descriptor chain, you can repeatedly call this function using the previous call's *next pointer in the *desc parameter.

You are responsible for properly allocating memory for the creation of both the descriptor under construction as well as the next descriptor in the chain. Descriptors must be in a memory device hosted by the SG-DMA controller’s chain read and chain write Avalon® host ports. Care must be taken to ensure that both *desc and *next point to areas of memory hosted by the controller.