LSI Symbios SYM53C040, Technical Manual

Page: 88 / 214

4-16 SCSI and DMA Registers
Register: 0xFC12
DMA Source/Destination Low (DSDL)
Read/Write
DSDL[7:0] DMA Source/Destination Low [7:0]
These register bits store the least significant byte of the
DMA function’s source address for send transfers and
destination address for receive transfers. The read value
of the DSDL and
DMA Source/Destination High (DSDH)
registers tracks the current source/destination address of
the transfer. If the transfer is interrupted for any reason,
the DSDL and DSDH registers will hold the next address
required, in case the interrupted transfer resumes.
Register: 0xFC13
DMA Source/Destination High (DSDH)
Read/Write
DSDH[7:0] DMA Source/Destination High [7:0]
These register bits store the most significant byte of the
DMA function’s source address for send transfers and
destination address for receive transfers. The read value
of the
DMA Source/Destination Low (DSDL) and DSDH
registers tracks the current source/destination address of
the transfer. If the transfer is interrupted for any reason,
the DSDL and DSDH registers hold the next address
required, in case the interrupted transfer resumes.
7 6 5 4 3 2 1 0
DSDL7 DSDL6 DSDL5 DSDL4 DSDL3 DSDL2 DSDL1 DSDL0
Defaults:
0 0 0 0 0 0 0 0
7 6 5 4 3 2 1 0
DSDH7 DSDH6 DSDH5 DSDH4 DSDH3 DSDH2 DSDH0 DSDH0
Defaults:
0 0 0 0 0 0 0 0