4-48
Registers
OLF1
SODL Most Significant Byte Full
5
This bit is set when the most significant byte in the
contains data. The SODL
register is the interface between the DMA logic and the
SCSI bus. In synchronous mode, data is transferred from
the host bus to the SODL register, and then to the SCSI
Output Data Register (SODR, a hidden buffer register
which is not accessible) before being sent to the SCSI
bus. In asynchronous mode, data is transferred from the
host bus to the
register,
and then to the SCSI bus. The SODR buffer register is
not used for asynchronous transfers. It is possible to use
this bit to determine how many bytes reside in the chip
when an error occurs.
FF4
FIFO Flags, Bit 4
4
This is the most significant bit in the SCSI FIFO Flags
field, with the rest of the bits in
. For a complete description of this field, see the
definition for
bits [7:4].
SPL1
Latched SCSI parity for SD[15:8]
3
This active HIGH bit reflects the SCSI odd parity signal
corresponding to the data latched into the most
significant byte in the
register.
DIFF
Diffsens Mismatch
2
This bit is set when the DIFFSENS pin detects a SE or
LVD SCSI operating voltage level while the LSI53C896 is
operating in HVD mode (by setting the DIF bit in the
register). If this bit is cleared, the
DIFFSENS value matches the DIF bit setting.
LDSC
Last Disconnect
1
This bit is used in conjunction with the Connected (CON)
bit in
. It allows the user to
detect the case in which a target device disconnects, and
then some SCSI device selects or reselects the
LSI53C896 SCSI function. If the Connected bit is
asserted and the LDSC bit is asserted, a disconnect is
indicated. This bit is set when the Connected bit in
SCNTL1 is off. This bit is cleared when a Block Move
instruction is executed while the Connected bit in
SCNTL1 is on.
*
Содержание LSI53C896
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 88: ...2 62 Functional Description...
Страница 112: ...3 24 Signal Descriptions...
Страница 306: ...6 38 Specifications This page intentionally left blank...
Страница 310: ...6 42 Specifications This page intentionally left blank...
Страница 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Страница 340: ...6 72 Specifications...
Страница 346: ...A 6 Register Summary...
Страница 362: ...IX 12 Index...