Register: 0x0E (0x8E)

SCSI Status One (SSTAT1)

Read Only

7

 

 

 

4

3

2

1

0

 

 

FF[3:0]

 

SDPL

MSG

C/D

I/O

 

 

 

 

 

 

 

 

 

0

0

 

0

0

x

x

x

x

 

 

 

 

 

 

 

 

 

FF[3:0]

 

FIFO Flags

 

 

 

 

[7:4]

These four bits define the number of bytes that currently reside in the LSI53C810A’s SCSI synchronous data FIFO. These bits are not latched and they will change as data moves through the FIFO. The FIFO can hold up to 9 bytes. Values over nine will not occur.

[

 

 

 

 

Bytes or Words in

FF3

FF2

FF1

FF0

the SCSI FIFO

 

 

 

 

 

0

0

0

0

0

 

 

 

 

 

0

0

0

1

1

 

 

 

 

 

0

0

1

0

2

 

 

 

 

 

0

0

1

1

3

 

 

 

 

 

0

1

0

0

4

 

 

 

 

 

0

1

0

1

5

 

 

 

 

 

0

1

1

0

6

 

 

 

 

 

0

1

1

1

7

 

 

 

 

 

1

0

0

0

8

 

 

 

 

 

1

0

0

1

9

 

 

 

 

 

SDPL Latched SCSI Parity3

This bit reflects the SCSI parity signal (SDP/), corresponding to the data latched in the SCSI Input Data Latch (SIDL). It changes when a new byte is latched into the SCSI Input Data Latch (SIDL) register. This bit is active high, in other words, it is set when the parity signal is active.

5-24

Operating Registers

Page 98
Image 98
LSI 53C810A Register 0x0E 0x8E, Scsi Status One SSTAT1 Read Only, FF30 Fifo Flags, Sdpl Latched Scsi Parity3