QL5064 QuickPCI Data Sheet
5.0 DMA Feature Overview
Each Master-mode FIFO has its own DMA controller to support maximum data throughput. Combining
one Initiator-Mode Transmit FIFO with one Initiator-Mode Receive FIFO also supports DMA Chaining.
This unique and flexible DMA chaining mode permits a 'linked-list' of transfers to be completed by the
DMA controller without software or processor intervention.
DMA Registers are accessible by the FPGA (back-end interface), as well as the PCI bus.
DMA Chaining descriptors are made of 4 64-bit Quad-Words, or 32 bytes of data per descriptor. Each
descriptor defines a DMA transaction (memory start location, size, read/write) as well as 88 bits of user-
defined information (such as a descriptor identifier, or back-end address).
DMA Chaining is a powerful DMA feature, allowing the QL5064 device to drive continuous pre-defined
DMA transactions with no processor or software interaction.
Single PCI Access (SPCI) reads and writes are supported for single quad-word transfers that do not
require FIFOs. SPCI supports IO reads and writes, configuration reads and writes, special cycles,
interrupt acknowledge cycles, as well as standard memory read/write transactions.
Figure 3: DMA Chaining Descriptor
User Defined (63:0)
(local address)
First PCI Address
Transfer Count (bytes)
(31:0)
User Defined
(23:0)
Next Descriptor Pointer Address (63:0)
63
0 Offset
0 x
00
0 x
08
0 x
10
0 x
18
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7
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