Command Format And Answer Format; Protocol For Data Transmission And Reception; Basic Procedure - Denon DN-780R Service Manual

Ver 1.00

1.3 Command format and answer format

The commands and answers consist of command code (CC) , parameter codes (PC) and some control
codes. The commands are transmitted from the host to the device and answers are transmitted from
the device to the host.
characters ( BCC ) to check the completion of command transport.
Here are the formats.
Commands ：<STX> <CC> <PC0> <PC1> <PC2> <-----> <PCn> <ETX> <BCCH><BCCL>
STX(Start of TeXt)
CC(Command Code)
PC(Parameter Code)
ETX(End of TeXt)
BCC(Block Check Character)
Answers：<STX> <CC> <AC> <PC0> <PC1> <PC2> <-----> <PCn> <ETX><BCCH><BCCL>
STX(Start of TeXt)
RC(Reply Code)
AC(Answer Code)
PC(Parameter Code)
ETX(End of TeXt)
BCC(Block Check Character)

1.4 Protocol for data transmission and reception

This device is based on half-duplex communication. The unit shall therefore transmit commands and
receive answers according to the following procedure.
1.4.1

Basic procedure

a) The host shall select commands for this device and transmit them to this unit.0
b) After sending a command, the host shall receive an answer from this device, then send the next
command.
c) The host shall analyze the RC, AC, and PC in answers and decide whether command has been
executed.
d) To get more information after received an answer, the host can send a status request command.
e) The time from the start of command transmission to the end should be max 40 msec.
f) The time from the completion of command transmission to the start of answer-back is 5 sec max.
The host and device shall be designed to send and receive block check
：02h
：Command code
：Defined for each command
：03h
：
CC + PC0 + PC1 + PC2 + ----- + PCn + ETX = Xyh
(Each of X and Y is 4 bit long )
BCCH ( high-level byte ) = X as converted to an ASCII code
BCCL ( low-level byte ) = Y as converted to an ASCII code
：02h
： Reply code(=Command code)
：Answer code
：Defined for each command
：03h
：
CC + PC0 + PC1 + PC2 + ----- + PCn + ETX = Xyh
(Each of X and Y is 4 bit long)
BCCH ( high-level byte ) = X as converted to an ASCII code
BCCL ( low-level byte ) = Y as converted to an ASCII code
( contents and number of parameters )
X , Y=0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
( contents and number of parameters )
X , Y=0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
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