25.2 Features

The following are key features of the DMAC:

  • Data transfer from:
    • Peripheral to peripheral
    • Peripheral to memory
    • Memory to peripheral
    • Memory to memory
  • Transfer trigger sources
    • Software
    • Events from Event System
    • Dedicated requests from peripherals
  • SRAM based transfer descriptors
    • Single transfer using one descriptor
    • Multi-buffer or circular buffer modes by linking multiple descriptors
  • Up to 32 channels
    • Enable 32 independent transfers
    • Automatic descriptor fetch for each channel
    • Suspend/resume operation support for each channel
  • Flexible arbitration scheme
    • 4 configurable priority levels for each channel
    • Fixed or round-robin priority scheme within each priority level
  • From 1 to 256 KB data transfer in a single block transfer
  • Multiple addressing modes
    • Static
    • Configurable increment scheme
  • Optional interrupt generation
    • On block transfer complete
    • On error detection
    • On channel suspend
  • 8 event inputs
    • One event input for each of the 8 least significant DMA channels
    • Can be selected to trigger normal transfers, periodic transfers or conditional transfers
    • Can be selected to suspend or resume channel operation
  • 4 event outputs
    • One output event for each of the 4 least significant DMA channels
    • Selectable generation on AHB, block, or transaction transfer complete
  • Error management supported by write-back function
    • Dedicated Write-Back memory section for each channel to store ongoing descriptor transfer
  • CRC polynomial software selectable to
    • CRC-16 (CRC-CCITT)
    • CRC-32 (IEEE® 802.3)