LSI 53C810A Manual De Usuario
6-20
Instruction Set of the I/O Processor
•
An I/O command structure must have all four bytes
contiguous in system memory, as shown below. The
offset/period bits are ordered as in the
contiguous in system memory, as shown below. The
offset/period bits are ordered as in the
register. The configuration bits are ordered
as in the
register.
Use this bit only in conjunction with the Select, Reselect,
Wait Select, and Wait Reselect instructions. Use bits 25
and 26 individually or in combination to produce the
following conditions:
Wait Select, and Wait Reselect instructions. Use bits 25
and 26 individually or in combination to produce the
following conditions:
Direct
Uses the device ID and physical address in the
instruction.
Uses the device ID and physical address in the
instruction.
Table Indirect
Uses the physical jump address, but fetches data using
the table indirect method.
Uses the physical jump address, but fetches data using
the table indirect method.
Relative
Uses the device ID in the instruction, but treats the
alternate address as a relative jump.
Uses the device ID in the instruction, but treats the
alternate address as a relative jump.
Config
ID
Offset/period
00
Bit 25
Bit 26
Direct
0
0
Table Indirect
0
1
Relative
1
0
Table Relative
1
1
Command
ID
Not Used
Not Used
Absolute Alternate Address
Command
Table Offset
Absolute Jump Offset
Command
ID
Not Used
Not Used
Absolute Jump Offset