LSI Logic Confidential
15-96
Serial I/O Port
Copyright © 2001, 2002 by LSI Logic Corporation. All rights reserved.
GO
Load Current Address Buffer Registers
3
This bit is used to control when ADDR_PTR1 and
ADDR_PTR2 for a particular DMA channel are loaded
into the “current buffer” address registers (ADDR_PTR3
and ADDR_PTR4) in double-buffer mode operation.
Note:
DoMiNo always runs in double-buffer mode. Single-buffer
(ring buffer) mode is not supported.
Note:
The maximum size for each SDRAM buffer transfer is 511
bytes. Therefore, the difference between ADDR_PTR2 and
ADDR_PTR1 should not exceed 511.
Go is set by software after the address range for the “next
buffer” is programmed (ADDR_PTR1/ADDR_PTR2).
Go is cleared by the hardware after these “next values”
are loaded. It is also cleared on reset.
MODE
Transfer Mode Select
2
This bit must always be set to ‘1’ so that the channel
operates in double-buffer mode.
FLUS
FIFO Flush
1
This is a self-clearing bit for flushing the DMA channel’s
two internal FIFOs.
1 = For transmit channels, all data currently in the chan-
nel FIFOs is dropped.
1 = For receive channels, all data currently in the channel
FIFOs is sent to the SDRAM address indicated by
ADDR_PTR3.
Setting FLUS does not terminate a transfer; it merely
dumps data (if transmit) or sends whatever data remains
in the FIFOs up to the SDRAM (if receive).
CHEN
DMA Channel Enable
0
This bit enables/disables the DMA channel. If CHEN is
cleared during a DMA operation, DMA is paused. Set
CHEN again to resume the DMA operation. All state
information is preserved when DMA is paused, and the
DMA operation continues from where it left off.
CHEN is controlled by software. It must be cleared once
the DMA operation has finished. On reset, CHEN is 0.
Содержание DMN-8600
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