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62 PCI-5565PIORC* Ultrahigh Speed Fiber-Optic Reflective Memory with Interrupts
Publication No. 500-9367855565-000 Rev. D.0
3. To initiate and monitor the transfer, access DMACSR0 as follows:
DMA channel 0 Command/Status register:
DMACSR0 at P offset $A8.
Write $0003 to start the transfer, then poll the same register.
When Bit 4 is high (1), the DMA cycle is complete.
NOTE
Polling read cycles take priority over the DMA cycles. Overly aggressive polling will slow the DMA
transfer. Rather than polling for the DMA done condition, the user can choose to enable the PCI interrupt
on DMA done by setting Bit 18 of the INTCSR at offset $68 to high (1). Once the interrupt is enabled, the
user software routine waits for the interrupt to occur.
4. After the DMA is finished, clear the DMA completion bit with a write to
DMACSR0 as follows. This is necessary when using DMA interrupts.
DMA channel 0 Command/Status register:
DMACSR0 at P offset $A8.
Write $8 to clear the DMA completion bit before attempting
another DMA.
Table 3-51 DMA Channel 0 Mode Settings
DMA channel 0 mode setting:
Bit 9 set to 1 indicates the use of Scatter-Gather
DMA (not normal Block mode).
DMAMODE0 at P offset $80
DMA channel 0 PCI starting address:
This register is unused during Scatter-Gather
DMA.
DMAPADR0 at P offset $84
DMA channel 0 local starting address:
Set to the starting address of the local (RFM)
memory (for either source or destination
transfers).
NOTE
: The first local (RFM) memory location
is at $0.
DMALADR0 at P offset $88
DMA channel 0 transfer size:
Set to the total number of bytes to be
transferred in all blocks (maximum $7FFFFF).
DMASIZ0 at P offset $8C
DMA channel 0 Descriptor Pointer:
Set bits 31:4 to the PCI Address of the first
DMA Scatter-Gather descriptor location.
Set bit-3 to 0 for PCI-to-Local
or set bit-3 to 1 for Local-to-PCI.
DMADPR0 at P offset $90
DMA channel 0 PCI DAC upper address:
This register is unused during Scatter-Gather
DMA.
DMADAC0 at P offset $B4