Tamarisk
®
640
Software ICD
10
2.3.2 ACK Response
The ACK response is a general-purpose acknowledgement that a command has been
received. Some commands will result in two ACK messages – one generated upon receipt
of the command and a second generated upon completion of the command. The ACK
message contains the ID of the command being acknowledged.
Table 5 –ACK Response Format
Byte
Value/Type
Description
1
0x01
Start of message.
2
0x02
ACK Response ID.
3
0x02
ACK responses always have 2 parameter bytes.
4, 5
Command ID
ID of command that is being ACK’d. Command IDs are 8 bits
in commands but are extended to 16 bits in an ACK.
6
checksum
Frame check sequence. See paragraph 2.1.
2.3.3 NAK Response
The NAK response is generated to indicate a command cannot be processed for some
reason. The Tamarisk
®
640
architecture currently does not use the NAK response.
Table 6– NAK Response Format
Byte
Value/Type
Description
1
0x01
Start of message.
2
0x03
NAK Response ID.
3
0x02
NAK responses always have 2 parameter bytes.
4, 5
Command ID
ID of command that is being NAK’d. Command IDs are 8 bits
in commands but are extended to 16 bits in an NAK.
6
checksum
Frame check sequence. See paragraph 2.1.
2.3.4 ERR Response
The ERR response is generated when a command is not recognized or when an error occurs
during the processing of a command. There are two formats for the ERR response. The first
format contains only the ID of the command that generated the error. The second format
contains an informative text message.
Table 7– ERR ID Response Format
Byte
Value/Type
Description
1
0x01
Start of message.
2
0x04
ERR Response ID.
3
0x02
ERR responses always have 2 parameter bytes.
4, 5
Command ID
ID of command that caused ERR. Command IDs are 8 bits in
