Embedded Peripherals IP User Guide

ID 683130
Date 8/11/2025
Public
Document Table of Contents
1. Introduction 2. Avalon® -ST Single-Clock and Dual-Clock FIFO Cores 3. Avalon® -ST Serial Peripheral Interface Core 4. SPI Core 5. SPI Agent/JTAG to Avalon® Host Bridge Cores 6. Intel eSPI Agent Core 7. eSPI to LPC Bridge Core 8. Ethernet MDIO Core 9. Intel FPGA 16550 Compatible UART Core 10. 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. Intel FPGA Avalon® Compact Flash Core 17. EPCS/EPCQA Serial Flash Controller Core 18. Intel FPGA Serial Flash Controller Core 19. Intel FPGA Serial Flash Controller II Core 20. Intel FPGA Generic QUAD SPI Controller Core 21. Intel FPGA Generic QUAD SPI Controller II Core 22. Interval Timer Core 23. Intel FPGA Avalon FIFO Memory Core 24. On-Chip Memory (RAM and ROM) Intel FPGA IP 25. On-Chip Memory II (RAM or ROM) Intel FPGA IP 26. Optrex 16207 LCD Controller Core 27. PIO Core 28. PLL Cores 29. DMA Controller Core 30. Modular Scatter-Gather DMA Core 31. Scatter-Gather DMA Controller Core 32. SDRAM Controller Core 33. Tri-State SDRAM Core 34. Video Sync Generator and Pixel Converter Cores 35. Intel FPGA Interrupt Latency Counter Core 36. Performance Counter Unit Core 37. Vectored Interrupt Controller Core 38. Avalon® -ST Data Pattern Generator and Checker Cores 39. Avalon® -ST Test Pattern Generator and Checker Cores 40. System ID Peripheral Core 41. Avalon® Packets to Transactions Converter Core 42. Avalon® -ST Multiplexer and Demultiplexer Cores 43. Avalon® -ST Bytes to Packets and Packets to Bytes Converter IP 44. Avalon® -ST Delay Core 45. Avalon® -ST Round Robin Scheduler Core 46. Avalon® -ST Splitter Core 47. Avalon® -MM DDR Memory Half Rate Bridge Core 48. Intel FPGA GMII to RGMII Converter Core 49. HPS GMII to RGMII Adapter Intel® FPGA IP 50. Intel FPGA MII to RMII Converter Core 51. HPS GMII to TSE 1000BASE-X/SGMII PCS Bridge Core Intel® FPGA IP 52. Intel FPGA HPS EMAC to Multi-rate PHY GMII Adapter Core 53. Intel FPGA MSI to GIC Generator Core 54. Cache Coherency Translator Intel® FPGA IP 55. Altera ACE5-Lite Cache Coherency Translator 56. Lightweight UART Core

29.4.1. HAL System Library Support

The Intel-provided driver implements a HAL DMA device driver that integrates into the HAL system library for Nios® II and Nios® V processors systems. HAL users should access the DMA controller via the familiar HAL API, rather than accessing the registers directly.

If your program uses the HAL device driver to access the DMA controller, accessing the device registers directly interferes with the correct behavior of the driver.

The HAL DMA driver provides both ends of the DMA process; the driver registers itself as both a receive channel (alt_dma_rxchan) and a transmit channel (alt_dma_txchan). The Nios® II Software Developer’s Handbook provides complete details of the HAL system library and the usage of DMA devices.

ioctl() Operations

ioctl() operation requests are defined for both the receive and transmit channels, which allows you to control the hardware-dependent aspects of the DMA controller. Two ioctl() functions are defined for the receiver driver and the transmitter driver: alt_dma_rxchan_ioctl() and alt_dma_txchan_ioctl(). The table below lists the available operations. These are valid for both the transmit and receive channels.

Table 300.  Operations for alt_dma_rxchan_ioctl() and alt_dma_txchan_ioctl()
Request Meaning
ALT_DMA_SET_MODE_8 Transfers data in units of 8 bits. The parameter arg is ignored.
ALT_DMA_SET_MODE_16 Transfers data in units of 16 bits. The parameter arg is ignored.
ALT_DMA_SET_MODE_32 Transfers data in units of 32 bits. The parameter arg is ignored.
ALT_DMA_SET_MODE_64 Transfers data in units of 64 bits. The parameter arg is ignored.
ALT_DMA_SET_MODE_128 Transfers data in units of 128 bits. The parameter arg is ignored.
ALT_DMA_RX_ONLY_ON (1) Sets a DMA receiver into streaming mode. In this case, data is read continuously from a single location. The parameter arg specifies the address to read from.
ALT_DMA_RX_ONLY_OFF (1) Turns off streaming mode for a receive channel. The parameter arg is ignored.
ALT_DMA_TX_ONLY_ON (1) Sets a DMA transmitter into streaming mode. In this case, data is written continuously to a single location. The parameter arg specifies the address to write to.
ALT_DMA_TX_ONLY_OFF (1) Turns off streaming mode for a transmit channel. The parameter arg is ignored.
Notes :
  1. These macro names changed in version 1.1 of the Nios® II Embedded Design Suite (EDS). The old names (ALT_DMA_TX_STREAM_ON, ALT_DMA_TX_STREAM_OFF, ALT_DMA_RX_STREAM_ON, and ALT_DMA_RX_STREAM_OFF) are still valid, but new designs should use the new names.

Limitations

Currently the Intel-provided drivers do not support 64-bit and 128-bit DMA transactions.

This function is not thread safe. If you want to access the DMA controller from more than one thread then you should use a semaphore or mutex to ensure that only one thread is executing within this function at any time.