User’s Guide 21020285 D
Chapter 2 Hardware Essentials
Channel Attention Port Page 2 - 11
Command List Channel Attention - To execute commands via Command
List, you must do the following:
1. Have an active Command List. (Command Lists are begun by issuing
the Start Command List command via a Single Command Structure.) If
you attempt to issue a command via Command List when there is not an
active List, you will receive an error code of 11H in the Status Port.
2. Fill the next available Parameter Block in the Command List with the
command you wish to have executed.
3. Adjust the Command List Parameter Block IN Index to indicate
additional commands have been added.
4. Write a 1 to the Channel Attention Port, instructing the RF3880 a dapter
to begin executing the Parameter Block(s) contained in the Command
List structure.
If you have multiple Parameter Blocks ready in the space allocated for
Command List, you may issue separate Channel Attention writes or you
may issue one for the entire group.
Use an offset of 8H from your Base Address when writing to the
Channel Attention Port.
For more information about how to use the Command List Structure, see
Chapter 4, Command Operation.
ChannelAttention Port
Format
The Channel Attention Port is three bits wide with the following meaning:
TYP Channel Attention Type - Indicates the type of command (or
acknowledgment) being issued with a write to the Channel Attention Port.
00 ⇒ Single Command Issue.
01 ⇒ Command List Issue.
10 ⇒ Target Mode Selection area has been read.
(See Chapters 6, 7, and 8 for more information about Target Mode.)
BIT
210
0TYP
Table 8: Channel Attention