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DC Power
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DC-10/DC-20
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8. Appendix
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(4) Acknowledgment message transmitted from DC
DC judges whether it is a Write or Read command based on the incoming message.
When receiving a Read command, DC collects required data and transmits a 1-byte command
data as an acknowledgment message.
When receiving a Write command, DC evaluates the incoming command + data and transmits an
acknowledgment message including a 1-byte command status to HOST.
For details on the command statuses, see the list in Table 8-3.
Table 8-3: Overview of command status
Command Description
0x00 Command OK This indicates that the command is correctly received.
0x01 Command Not OK This indicates that the command is not defined.
0x02 Data Range NG This indicates that the data is outside the range of selection.
0x03 Check Sum Error This indicates that the checksum values of the data are wrong.
0x05 Data Length NG This indicates that there is an error in the received data length.
(5) Receipt of acknowledgment message on HOST
HOST can judge the transmitted data with the acknowledgment message.
If the ACK is received and the acknowledgment message is 0x00, it indicates that DC has received the
message and the process is completed as expected.
If the command status is not 0x00 even after the receipt of NAK or ACK, DC has not received correct
messages.
* If this happens, check the command to see if there are any errors in the commands or data.
After HOST receives an acknowledgment message from DC, send ACK to DC.
(6) Receipt of ACK/NAK on DC
DC returns to the waiting mode after receiving ACK and then goes into the mode where it can receive
the next message.
If no ACK is received, the ACK waiting mode continues.
The ACK waiting mode automatically recovers approx. 4 seconds after an acknowledgment message of
DC is sent, and goes into the message waiting mode.