Sony hsr-1-1p User Manual
4
Communication Protocol
Communication is carried out in units of bytes in the
following procedure. When the computer sends one
byte of data, it waits for a return from the VTR before
sending the next byte. The return from the VTR may
not only be one byte of data, but can be multiple bytes
of data. For a command, such as EJECT, which takes
time to execute, not only the return immediately after
receipt of the command is issued, but a return
indicating the result of execution upon completion of
operation is also issued. The command, the return
from the VTR, and parameters are all defined as the
command in the RS-232C protocol.
following procedure. When the computer sends one
byte of data, it waits for a return from the VTR before
sending the next byte. The return from the VTR may
not only be one byte of data, but can be multiple bytes
of data. For a command, such as EJECT, which takes
time to execute, not only the return immediately after
receipt of the command is issued, but a return
indicating the result of execution upon completion of
operation is also issued. The command, the return
from the VTR, and parameters are all defined as the
command in the RS-232C protocol.
Commands to operate the VTR
When a command (CMD) has no parameter:
When a command (CMD) has parameters (PARAM.):
There are three kinds of returns from the VTR: ACK,
NAK, and ERROR.
ACK: Returned when data is correctly returned.
NAK: Returned when communication error is
NAK, and ERROR.
ACK: Returned when data is correctly returned.
NAK: Returned when communication error is
detected or an unidentified command is received.
ERROR: Returned when a command cannot be
executed because of tape slack and other errors.
Commands to sense VTR status
Commands from the VTR to the computer
to notify of completion of an operation
to notify of completion of an operation
This return is issued when execution of the following
commands is completed: EJECT, FRAME SEARCH,
T/D SEARCH, and ALARM SEARCH.
commands is completed: EJECT, FRAME SEARCH,
T/D SEARCH, and ALARM SEARCH.
There are three kinds of return from the VTR:
COMPLETION, NOT TARGET, and CASSETTE
OUT.
COMPLETION: Returned when command
COMPLETION, NOT TARGET, and CASSETTE
OUT.
COMPLETION: Returned when command
execution is correctly completed.
NOT TARGET: Returned when the target point
specified by the command cannot be found.
CASSETTE OUT: Returned when the cassette is
ejected.
Extended commands
A command consists basically of one byte. Some
commands may function when combined with another
command.
commands may function when combined with another
command.
Notes
• Do not send the next command before receiving the
return from the VTR.
If the return from the VTR is not received within 10
msec or more after the transmission is completed,
appropriate processing must be executed because the
communication is judged not executed correctly.
If the return from the VTR is not received within 10
msec or more after the transmission is completed,
appropriate processing must be executed because the
communication is judged not executed correctly.
• Do not send any other command between the
extended command and the secondary command.
RxD
TxD
TxD
3AH
0AH
CMD
RET
RxD
TxD
TxD
3AH
0AH
3AH
0AH
3AH
0AH
CMD
PARAM.
PARAM.
RET
RET
RET
RxD
TxD
TxD
DAH
0AH
CAH
31H
Extended
CMD
Secondary
CMD
RET
RET
RxD
TxD
TxD
2AH
0AH
03H
CMD
RET
CASSETTE
OUT
RxD
TxD
TxD
DAH
0AH
C7H
xxH
xxH
xxH
xxH
EXP-3
CMD
ACK
DATA DATA DATA DATA