Avago Technologies LSI53C876E - Manual (Page 140)

4-46 Registers
SDP0/ SCSI SDP0/ Parity Signal 0
This bit represents the active high current status of the
SCSI SDP0/ parity signal. This signal is not latched and
may change as it is read.
Register: 0x0E
SCSI Status One (SSTAT1)
Read Only
FF[3:0] FIFO Flags [7:4]
These four bits, along with SCSI Status Two (SSTAT2) ,
bit 4, define the number of bytes or words that currently
reside in the LSI53C876 SCSI synchronous data FIFO as
shown in
Table 4.6 . These bits are not latched and they
will change as data moves through the FIFO. Because
the FIFO can only hold either 16 bytes or 16 words,
values over 16 cannot occur.
.
7 4 3 2 1 0
FF[3:0] SDPOL MSG C_D I_O
0 0 0 0 x x x x
Table 4.6 SCSI Synchronous Data FIFO Word
Count
FF4
(SSTAT2 bit 4) FF3 FF2 FF1 FF0
Bytes or
Words in
the SCSI
FIFO
0 0 0 0 0 0
0 0 0 0 1 1
0 0 0 1 0 2
0 0 0 1 1 3
0 0 1 0 0 4
0 0 1 0 1 5
0 0 1 1 0 6
0 0 1 1 1 7
0 1 0 0 0 8
0 1 0 0 1 9