SCSI Registers
4-23
Register: 0x00
SCSI Control Zero (SCNTL0)
Read/Write
ARB[1:0]
Arbitration Mode Bits 1 and 0
[7:6]
A combination of the ARB bits selects either Simple or
Full arbitration.
Simple Arbitration
1.
The LSI53C1000 waits for a bus free condition to
occur.
2.
It asserts SBSY/ and its SCSI ID, contained in the
register, onto the SCSI bus. If
the SSEL/ signal is asserted by another SCSI
device, the LSI53C1000 deasserts SBSY/,
deasserts its ID, and sets the Lost Arbitration bit
(bit 3) in the
register.
3.
After an arbitration delay, the CPU should read the
register to check if a
higher priority SCSI ID is present. If no higher
priority ID bit is set, and the Lost Arbitration bit is not
set, the LSI53C1000 wins arbitration.
4.
Once the LSI53C1000 wins arbitration, SSEL/ is
asserted using the
for a bus clear and a bus settle delay
(1.2
µ
s). Then, a low level selection is performed.
7
6
5
4
3
2
1
0
ARB[1:0]
START
WATN
EPC
CRCOK
AAP
TRG
1
1
0
0
0
x
0
0
ARB1
ARB0
Arbitration Mode
0
0
Simple arbitration
0
1
Reserved
1
0
Reserved
1
1
Full arbitration, selection/reselection
Содержание LSI53C1000
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 28: ...1 12 Introduction...
Страница 234: ...4 124 Registers...
Страница 314: ...6 40 Specifications This page intentionally left blank...
Страница 318: ...6 44 Specifications This page intentionally left blank...
Страница 344: ...6 70 Specifications This page intentionally left blank...
Страница 350: ...6 76 Specifications Figure 6 42 LSI53C1000 329 Ball Grid Array Bottom view...
Страница 352: ...6 78 Specifications...
Страница 360: ...A 8 Register Summary...
Страница 376: ...IX 12 Index...