4.2.3.1 Continuous DMA—Operations

The following instructions describe running DMA operations between PC and DDR3L, PC and DDR4, PC and LSRAM:

  1. Select one of the following options from the DMA Transfer Type Selection drop-down list:

    • PC->DDR3L—to transfer the data from host PC to PolarFire DDR3L memory
    • DDR3L->PC—to transfer the data from PolarFire DDR3L memory to host PC
    • Both- PC<->DDR3L—to transfer the data from host PC to and from PolarFire DDR3L memory
    • PC->DDR4—to transfer the data from host PC to PolarFire DDR4 memory
    • DDR4->PC—to transfer the data from PolarFire DDR4 memory to host PC
    • Both PC<->DDR4—to transfer the data from host PC to and from PolarFire DDR4 memory
    • PC->LSRAM—to transfer the data from host PC to PolarFire LSRAM memory
    • LSRAM->PC—to transfer the data from PolarFire LSRAM memory to host PC
    • Both PC<->LSRAM—to transfer the data from host PC to and from PolarFire LSRAM memory
  2. Select Transfer Size (4 KB to 64 KB) from the drop-down list. The maximum contiguous DMA size is 64 KB, because the host PC may not have a contiguous memory of more than 64 KB. For DMA operations that require more than 64 KB, use SGDMA.
  3. Enter the Loop Count in the box.
  4. Click Start Transfer. After a successful DMA operation, the GUI displays the throughput and average throughput in MBps.
Important: The AXI LSRAM in the design is configured for 4 KB. This 4 KB is overwritten if more than 4 KB of DMA operation is performed on LSRAM. This option is provided to exercise the throughputs with larger DMA size.

The following figure shows the throughput and average throughput in MBps.

Figure 4-15. Continuous DMA Operations with DMA Transfer Type Selection as Both PC and LSRAM