LSI LSI53C896, Technical Manual

Page: 212 / 370

4-100 Registers
Register: 0x52
SCSI Test Four (STEST4)
Read Only
SMODE[1:0] SCSI Mode [7:6]
These bits contain the encoded value of the SCSI
operating mode that is indicated by the voltage level
sensed at the DIFFSENS pin. The incoming SCSI signal
goes to a pair of analog comparators that determine the
voltage window of the DIFFSENS signal. These voltage
windows indicate LVD, SE, or HVD operation. The bit
values are defined in the following table.
LOCK Frequency Lock 5
This bit is used when enabling the SCSI clock quadrupler,
which allows the LSI53C896 to transfer data at Ultra2
SCSI rates. Poll this bit for a 1 to determine that the clock
quadrupler has locked to 160 MHz. For more information
on enabling the clock quadrupler, refer to the descriptions
of
SCSI Test One (STEST1) , bits 2 and 3.
R Reserved [4:0]
Register: 0x53
Reserved
7 6 5 4 0
SMODE[1:0] LOCK R
0 0 0 0 0 0 0 0
Bits [7:6] Operating Mode
00 Not Possible
01 HVD or powered down (for HVD mode, the
DIF bit must also be set)
10 SE
11 LVD SCSI
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