Denon DN-A7100 User Manual page 45

TRANSMISSION DATA FORMAT
Transmission data format from Host to Slave
There are two kinds of transmission data form from Host shown below.
• Form1: Command
Command is a data that requests some status change.
Start character : '@'
COMMAND : see "Command list"
End character (CR) : 0Dh
start command
'@' "xxx:"+"..."
• Form2: Status request
Status request is a data that requests a answer of some status.
Start character : '@'
Request status : see "Status request list"
Request character : '?'
End character (CR) : 0Dh
start request status
'@' "xxx:?"+"..."
Transmission data format from Slave to Host
There are two kinds of transmission data form from Slave shown below.
• Form1: ACK/NAK
ACK is a reply data from Slave when Slave got an acceptable command data from Host.
(ACK is sent to Host when Slave has no related status by the Command.)
Start character : '@', ACK : 06h, End character (CR) : 0Dh
start ACK CR
'@' 06h 0Dh
NAK is a reply data from Slave when Slave got an incorrect Command data, Status request data or some
other data from Host.
Start character : '@', NAK : 15h, End character (CR) : 0Dh
start NAK CR
'@' 15h 0Dh
• Form2: Status answer and Auto status feedback
Status answers are reply data when Slave got an acceptable Request status or Command data from Host.
Auto status feedbacks are send to Host data when a Slave's status is changed.
Start character : '@'
Answer character : see "Status list"
End character (CR) : 0Dh
start status
'@' "xxx:"+"..."
42
end
0Dh
end
0Dh
end
0Dh
THE TRANSACTION SEQUENCES AND THE REGULATIONS
The transaction sequences
The transactions have three kinds of sequence.
* A transaction is a Command from Host then Slave will be an answer by Status answer, ACK or NAK.
* A transaction is a Status request from Host then Slave will be an answer by Status answer or NAK.
* A transaction is Auto status feedback from Slave when a Slave's status changed. (If the auto status feedback
is enabled.)
The transaction regulations
The transactions have some kinds of regulation.
* An answer (ACK, NAK or Status answer) transmittion by Slave has to fi nish within 500ms when got a
Command or a Status request from Host.
* Host must not transmit an another Command or Status request until "it receives a answer by a previous
Command or Status request" or "it passes a term of waitinng time from a fi nishing of previous transmission
of a Command or a Status request ".
* Slave has to fi nish a transaction under 500ms when it sends Auto status feedback data.
Specifi cation of Auto status feedback
There are some specifi c regulations about Auto status feedback.
* The product status has segmented into four layers of 1, 2, 3 and 4.
* The status of layer 1 are assigned most kindly status to Host. (The statuses of layer 2 are assigned kindly
status, the statuses of layer 3 are not so need status to Host and the statuses of layer 4 are probably no
wished statuses.)
* Each layer status can control transmit enable or disable by Host command. (The product default would be
all disables.)
* Slave sends auto status feedback by itself when the status is changed and if the status feedback is
enabled.
* The product defi ned and segmentationed layers are takeing in status list.
Example of the transactions
<Host>
max. 0.5 sec
Command
TxD
Status answer,
ACK or NAK
RxD
a transaction
Example of the transactions
<Slave>
Status
request
max. 0.5 sec
RxD
Status answer
TxD
a transaction