LSI Logic Confidential
9-12
Secondary Bitstream Interface
Copyright © 2001, 2002 by LSI Logic Corporation. All rights reserved.
While a DMA transfer is active, the Stop Address register should not be
reloaded with the address value of the Next Address register. It is
possible that the Next Address may hit the old Stop Address when the
Stop Address register is reloaded with a new value.
Note:
Reloads of the stop address must be synchronized with
DMA completion detection so that the DMA operation is not
restarted after the GO bit is cleared or a completion
interrupt is generated.
9.5.4
Secondary Base Address and Limit Address Registers
(CBus Addr: 0x08082C and 0x080830)
The Secondary Base Address register at control bus address 0x08082C
specifies the SDRAM address for the beginning of the circular SDRAM
buffer. The Secondary Limit Address register at control bus address
0x080830 specifies the SDRAM address for the first byte after the buffer.
When the next address reaches the value in the Secondary Limit
Address register, it is reloaded with the secondary base address register
value before transferring additional data. The two least significant and the
upper four bits of these registers must be zero.
9.5.5
Secpacksize Register (CBus Addr: 0x080834)
The Secondary Pack Size register at control bus address 0x080834
specifies the packet framing size for the secondary bitstream port in
bytes. The two least significant and the upper 16 bits must be zero.
9.5.6
SecPacketDelay Register (CBus Addr: 0x080838)
The secondary packet delay register at control bus address 0x080838
specifies the number of clocks from the start of one secondary bitstream
outgoing packet to the start of the next outgoing packet when packet
framing is enabled.
Содержание DMN-8600
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