AM53CF94 Advanced Micro Devices, AM53CF94 Datasheet - Page 37

• Manufacturer Part Number: AM53CF94
• Description: Enhanced SCSI-2 Controller (ESC)
• Manufacturer: Advanced Micro Devices

COMMANDS
The device commands can be broadly divided into two
categories, DMA commands and non-DMA commands.
DMA commands are those which cause data movement
between the host memory and the SCSI bus while non-
Summary of Commands
Initiator Commands
Information Transfer
Initiator Command Complete Steps
Message Accepted
Transfer Pad Bytes
Set ATN
Reset ATN
Target Commands
Send Message
Send Status
Send Data
Disconnect Steps
Terminate Steps
Target Command Complete Steps
Disconnect
Receive Message
Receive Command Steps
Receive Data
Receive Command Steps
DMA Stop Command
Access FIFO Command
Command
Command Code
DMA
Mode
Non-
1A
1B
2A
2B
10
11
12
18
20
21
22
23
24
25
27
28
29
04
05
(Hex.)
Am53CF94/Am53CF96
P R E L I M I N A R Y
DMA
Mode
AA
AB
A0
A1
A2
A3
A4
A5
A7
A8
A9
90
91
98
84
85
–
–
–
Idle State Commands
Reselect Steps
Select without ATN Steps
Select with ATN Steps
Select with ATN and Stop Steps
Enable Selection/Reselection
Disable Selection/Reselection
Select With ATN3 Steps
Reselect with ATN3 Steps
General Commands
No Operation
Clear FIFO
Reset Device
Reset SCSI bus
DMA commands are those that cause data movement
between the device FIFO and the SCSI bus. The MSB of
the command byte differentiate the DMA from the non-
DMA commands.
Command
Command Code
DMA
Mode
Non-
40
41
42
43
44
45
46
47
00
01
02
03
(Hex.)
AMD
DMA
Mode
C0
C1
C2
C3
C4
C5
C6
C7
80
81
82
83
37