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Avago Technologies LSI53C895A User Manual

Page 203

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SCSI Registers

4-95

timers by greatly reducing all three time-out periods.
Setting this bit starts all three timers and if the respective
bits in the

SCSI Interrupt Enable One (SIEN1)

register

are asserted, the LSI53C895A generates interrupts at
time-out. This bit is intended for internal manufacturing
diagnosis and should not be used.

CSF

Clear SCSI FIFO

1

Setting this bit causes the “full flags” for the SCSI FIFO
to be cleared. This empties the FIFO. This bit is
self-clearing. In addition to the SCSI FIFO pointers, the

SCSI Input Data Latch (SIDL)

,

SCSI Output Data Latch

(SODL)

, and (SODR, a hidden buffer register which is not

accessible) full bits in the

SCSI Status Zero (SSTAT0)

and

SCSI Status Two (SSTAT2)

are cleared.

STW

SCSI FIFO Test Write

0

Setting this bit places the SCSI core into a test mode in
which the FIFO is easily read or written. While this bit is
set, writes to the least significant byte of the

SCSI Output

Data Latch (SODL)

register cause the entire word

contained in the SODL to be loaded into the FIFO. These
functions are summarized in the table below.

Register

Name

Register

Operation

FIFO Bits

FIFO

Function

SODL

Write

[15:0]

Load

SODL0

Write

[7:0]

Load

SODL1

Write

[15:8]

None