Scsi input, Data latch (sidl), Scsi input data latch (sidl) – Avago Technologies LSI8751D User Manual

Page 193: Scsi, Input data latch (sidl), Scsi input data, Latch (sidl), Scsi input data latch, Sidl)

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5-77

SCSI Input Data Latch (SIDL)

,

SCSI Output Data Latch

(SODL)

, and SODR 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 this register to be loaded into the FIFO.
Writing the least significant byte of the

SCSI Output Data

Latch (SODL)

register will cause the FIFO to load. These

functions are summarized in the table below.

Register: 0x50–0x51 (0xD0–0xD1)

SCSI Input Data Latch (SIDL)
Read Only

SIDL

SCSI Input Data Latch

[15:0]

This register is used primarily for diagnostic testing,
programmed I/O operation, or error recovery. Data
received from the SCSI bus can be read from this
register. Data can be written to the

SCSI Output Data

Latch (SODL)

register and then read back into the

LSI53C875 by reading this register to allow loopback
testing. When receiving SCSI data, the data flows into
this register and out to the host FIFO. This register differs
from the

SCSI Bus Data Lines (SBDL)

register;

SCSI

Input Data Latch (SIDL)

contains latched data and the

SCSI Bus Data Lines (SBDL)

always contains exactly

what is currently on the SCSI data bus. The power-up
value of this register is indeterminate.

Register

Name

Register

Operation

FIFO Bits

FIFO

Function

SODL

Write

[15:0]

Load

SODL0

Write

[7:0]

Load

SODL1

Write

[15:8]

None

15

0

SIDL

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

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