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STP2002QFP
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
Sun Microsystems,
place.
Note: To determine the exact address at which an error occurred, two
cases have to be dealt with. These are the following:
Case 1:The error occurs on the SCSI Bus
For this case, the starting address of the block/command is known, as
this is programmed before any data movement between FAS366 and
SCSI DMA block takes place. Reading of transfer count register from
FAS366, would indicate the number of data bytes read/written. Using
the starting address and the byte count, the exact address can be calcu-
lated.
Case 2: The error occurs on the SBus
Data on the SBus is always moved in a DMA burst of byte/half-
word/word/double word for up to 64 bytes. A read of D_ADDR
register will indicate the address of the location at which the next burst
will take place. In a burst of 64/32/16 etc., if an error occurred on the
SBus, it will not be possible to identify the exact location at which an
error on SBus occurred.
7.3.3 SCSI Byte Count RegisterTable 44: SCSI Address Register Address
Register Physical Address Access Size
Address register (D_ADDR) 0x880_0004 4 bytes
Table 45: SCSI Address Register Definition
Field Bits Description Type
D_ADDR 31:0 Virtual address used in SCSI DVMA access R/W
Table 46: SCSI Byte Count Register Address
Register Physical Address Access Size
Byte Count register (D_BCNT) 0x880_0008 4 bytes
Table 47: SCSI Byte Count Register Definition
Field Bits Description Type
D_BCNT 31:0 DVMA transfer length counter R/W