Interphase Tech CONDOR 4221 User Manual
Page 83
Common IOPB Structures
71
Command Code
This field specifies the command to be executed. Particular values are noted for each of the individual commands.
Command Options
This field specifies operational parameters or options to be associated with the execution of the command. The
following subfields are available for all commands:
Table 3-15. Command Options
Interrupt Enable (IE)
When set, the controller interrupts the host upon completion of the command, using the normal interrupt level
and vector located in the IOPB if no error occurred, or the error interrupt level and vector otherwise.
Return Status
This field contains the returned status for the command. Any non-zero value indicates an error.
Normal Completion Level / Vector
This field contains the VMEbus interrupt level and vector used by the controller to notify the host of a successful
command completion. These values are ignored when a command is posted as a multiple completion.
Error Completion Level / Vector
This field contains the VMEbus interrupt level and vector used to return commands which complete with errors.
DMA Transfer Control Word
This field contains control information which governs the DMA transfer of data between the host and the controller.
The following subfields are defined:
Table 3-16. DMA Transfer Control Word
Command Options
Offst
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x01
IE
DMA Transfer Control Word
Offst
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x05
Reserved
DIR
TT
MT
Address modifier