LSI Logic Confidential
8-26
Host Slave Interface
Copyright © 2001, 2002 by LSI Logic Corporation. All rights reserved.
IE
4
If IE is set, a Master DMA completion interrupt is gener-
ated when a Master DMA transfer completes; otherwise
no interrupt is generated. If IE is clear, no Master com-
pletion interrupt is generated.
Incoming transfers are complete when the value of the
Master DMA Next Address register equals the value of
the Master DMA Stop Address register and the DMA data
has been written to SDRAM.
Outgoing transfers are complete when the value of the
Master DMA Next Address equals the value of Master
DMA Stop Address, and the DMA data has been trans-
ferred to the system–that is, when the DMA FIFO is
empty.
1 = Master completion interrupt enabled
0 = Master completion interrupt disabled
GO
3
GO is set by microcode to begin master DMA transfers.
The GO bit is cleared by hardware after the transfer is
completed.
Software that clears the GO bit when BSRD is clear
flushes the remaining contents of the master DMA
transfer FIFO to SDRAM and terminates the transfer
without generating an interrupt.
Clearing the GO bit when BSRD is set (outgoing transfer)
discards the remaining contents of the master DMA FIFO
and terminates the transfer. Software clearing the GO bit
in either direction will generate an interrupt if enabled
(IE bit is programmed to logic value 1). Since this flush
will take some time to complete, software should keep
polling the GO bit after writing zero until the GO bit reads
as zero to ensure that the last data has been written to
SDRAM.
During incoming transfers using the master DMA mode,
the master interface drops the last byte if the data was
received after the GO bit was cleared by software.
Note:
The GO bit should be cleared, only if necessary, and read
as zero before software changes the value of BSRD or any